The invention discloses a crowd sensing excitation method for random participation based on a crowd sensing system. The crowd sensing system comprises a control platform and a plurality of mobile users. According to the method, first, the control platform calculates task returns according to relative heat of sensing tasks; second, the control platform evaluates data quality of all the sensing tasks, measurement times needed by the sensing tasks are calculated according to a data quality increment in single measurement, decreasing steps of measurement returns are determined, and returns to participants in next measurement are further calculated; and last, the control platform publishes tasks information, the mobile users select the sensing tasks, execute measurement and upload sensing data, and the control platform sends corresponding returns to the mobile users. Through the method, limitations on the crowd sensing system by random participation and time-space correlation are better solved, the excitation demand for participating crowd sensing of the mobile users is met, the degree of balance of user participation is increased while the degree of completion of the crowd sensing tasks is increased, and meanwhile the total income of each participant is maximized.