Abstract: A core technology of cognitive radio is spectrum sensing. In this paper, we combine the incentive mechanism of crowd-sensing with cooperative spectrum sensing effectively, and put forward an cooperative spectrum sensing algorithm based on multi-task incentive mechanism. This algorithm considers about the detection probability and recognition time, and establishes utility functions of secondary users (SUs) who participate in the sensing. SUs get the optimal utilities by optimizing the recognition time, and determine which channel to sense. Under the budget constraint, the base station chooses the SUs to take part in the sensing with greedy algorithm. SUs will get some reward after they finish the sensing. The simulation results show that this algorithm can get multiple channels sensed, and promotes the cooperative detection probability effectively by stimulating the involvement of SUs.