Abstract: Position information of primary user is critical for communication between CR users in cognitive radio network. By cooperative location technology to improve the positioning performance has become a hot research direction in cognitive radio network recently. Based on RSSD/TDOA, a cooperative location algorithm is proposed in detail in this paper. The algorithm is suitable for the application scenarios that the priori knowledge is unknown such as transmit power and signal transmission instantaneous time of the primary user. Firstly the algorithm divide the consideration area into two cases: inner area and outer area by convex hull algorithm. Then the cooperative location algorithm based on RSSD/TDOA is adopted to estimate position of the primary user. Taylor series expansion algorithm is applied in order to enhance the location accuracy. In simulation results, we compare the performance and time of the RSSD, TDOA estimation and algorithm proposed in this paper. The result of simulation shows that the proposed algorithm has better performance of location and time duration comparing with other algorithms in cognitive radio field.