An algorithm of resource Allocation for OFDM-Based Cognitive Radio Systems is proposed in this paper considering the power and interference restricted condition simultaneously. Firstly, the subcarrier is allocated. And then the power is allocated to subcarrier based differential evolution algorithm to maximize the system total transmission rate with the condition of the interference caused from cognitive users to primary users and power condition. The simulation results show that the proposed algorithm in this paper can be efficiently control the power of secondary users', and achieve the resource equal allocation in cognitive radio network, which greatly improves the transmission rate of system with lower compute complexity.