A PU (Primary User) State-based Sequential Cooperative Spectrum Sensing (PSSCSS) algorithm was presented which based on the occupation characteristics of authorized channel and sequential spectrum sensing. The duration of PU's presence or absence in authorized channel is far greater than sensing period. Cognitive nodes perform different sequential spectrum sensing according to the sensing result of last time to improve the performance and efficiency of the system. The simulation results show that compared to the hard combination, soft combination and non PU state-based sequential cooperative spectrum sensing algorithm, this algorithm can greatly improves detection performance by smaller transmission bandwidth at the expense of little increase in time consumption.