In recent years, Chinese enterprises pay increasing attention environmental protection and actively deploy green management policies in response to the national carbon peaking and carbon neutrality policies. In practice, the implementation of the corporate green policies and the realization of carbon emission reduction goals depend on the participation and actions of individual employees. Thus, green human resource management attracts increasing research and practical attention. Considering the important role of employee green behavior in realizing corporate sustainable goals and improving environmental performance, stimulating employee green behavior has become the focus of corporate green management. Then, how does green human resource management influence employee green behavior? Previous research has shown that green human resource management has a positive impact on employee green behavior. Existing research has determined a series of intermediary mechanisms through which green human resource management promotes employee green behavior based on social information processing theory, self-determination theory, social identity theory, social exchange theory, cue consistency theory and signal theory. However, corporate green management policies do not always achieve the expected effect to improve employee green behavior, but may bring potential negative influence on employees. This inspires researchers to look more comprehensively at the consequences of green human resource management from both positive and negative sides. However, existing theoretical perspectives have all regarded green human resource management as a positive contextual factor or organizational signal, which can only explain why green human resource management positively influences employee green behavior. Therefore, it is necessary to explore the more comprehensive impact of green human resource management on employee green behavior from a new theoretical perspective. This research focuses on the theoretical perspective of resource conservation to explore the positive and negative effects of perceived green human resource management on employee green behavior as well as the underlying mechanisms. According to the conversation of resources theory, this research proposes that green human resource management has both the resource provision and resource consumption features. Therefore, on the one hand, it stimulates employees' green self-efficacy, an individual psychological resource, thus promoting employee green behavior (the resource gain path). On the other hand, it triggers perceived role overload of employees, a state of individual resource loss, thus negatively influencing employee green behavior (the resource loss path). In addition, this paper proposes that the individual trait of employee regulatory focus can moderate the above-mentioned resource gain and resource loss mechanisms. Specifically, employee promotion focus weakens the positive impact of green human resource management on employee green behavior through green self-efficacy (resource gain path), and weakens the negative impact of green human resource management on employee green behavior through perceived role overload (resource loss path). Employee prevention focus strengthens the resource loss path and weakens the resource gain path. We conducted a field survey by collecting multi-wave multi-source (employee-supervisor dyads) questionnaire data (N=306). Consistent with our hypotheses, the results show that: 1) Perceived green human resource management has a double-edged sword effect on employee green behavior. Green human resource management can exert positive and negative influence on employee green behaviors through green self-efficacy and perceived role overload, respectively. 2) Employee promotion focus weakens the positive relationship between perceived green human resource management and green self-efficacy, but it does not moderate the relationship between perceived green human resource management and perceived role overload; employee prevention focus strengthens the negative relationship between perceived green human resource management and perceived role overload, but it does not moderate the relationship between perceived green human resource management and green self-efficacy. 3) Employee promotion focus weakens the positive impact of perceived green human resource management on employee green behavior through green self-efficacy, and employee prevention focus enhances the negative impact of perceived green human resource management on employee green behavior through perceived role overload. This research mainly makes theoretical contributions in three ways. First, by revealing the double-edged influence of green human resource management on employee green behavior, this study expands the research on the influence of green human resource management on employee green behavior and provides a more comprehensive insight for this research topic. Second, this study introduces the conservation of resources theory into the field of green behavior, which enriches the theoretical mechanism through which green human resource management affects employee green behavior. Specifically, from the theoretical perspective of resource conservation, this paper determines the dual mediating mechanisms of green human resource management affecting employee green behavior through employee green self-efficacy (resource gain path) and perceived role overload (resource loss path). Hence, this research expands the relevant theories of studying employee green behavior. Thirdly, this research enriches the boundary conditions of green human resource management affecting employee green behavior. Specifically, by revealing the moderating effects of employee regulatory focus (promotion and prevention focus) on the resource gain and resource loss paths, this study not only helps us further understand when green human resource management has a double-edged sword effect on employee green behavior, but also further improves the theoretical understanding of this research topic.