Abstract: In global climate governance, the process of greenhouse gas emission reduction is in a fix. From the perspective of“negative externality power”, the paper explains why the state actors have insufficient willingness and action to reduce their negative externality. It suggests that negative externality is a sort of power resource. Under certain circumstances, the actor producing negative externality is able to bargain with other actors to increase its own benefits or make itself in a favorable position.Therefore, negative externality power can contribute to one's relational power as well as structural power. In climate politics, state actors, especially big emitters, tend to use negative externality power to influence the overall negotiation process and other actors to gain benefits. Through case study, the paper argues that in international climate politics the United States mainly uses negative external power in a negative manner while the European Union is a typical example which positively uses the power.China also has more and more negative external power resources nowadays. In order to better solve the problem of negative externality, state actors should recognize the objectivity and universality of the existence of negative externality power, and use it within a reasonable limit.