Because of the characteristics of Cognitive Radio Networks(CRN), cooperative spectrum sensing is vulnerable to a variety of attacks. Considering the cooperative spectrum sensing under the Spectrum Sensing Data Falsification(SSDF) attack in CRN, the SSDF attacker and the fusion center’s behavior and payoff under different conditions are analyzed based on the game theory, and the best strategy for both sides from the view of game theory is studied. When the cooperative sensing fusion center adopts the proposed method, the SSDF attack can be resisted effectively, while the SSDF attacker cannot get more profits through adjusting its own strategy.