A method for extracting fan vibration characteristics based on a cyclostationary method for a complex amplitude modulation model comprises the following steps that a vibration acceleration signal of afan is collected through an acceleration sensor; the collected acceleration signal is guided into a to-be-operated procedure, detecting is conducted through a correlation characteristic function based on cyclostationary characteristics, and a cyclic density spectrum is obtained; through priori knowledge of the complex amplitude modulation model of a rotating machine, a three-dimensional cyclic density spectrum and a two-dimensional top view, reducing the amplitude value difference, of the three-dimensional cyclic density spectrum are constructed; the modulation frequency is judged according to the two-dimensional top view, and the carrier frequency is judged according to the three-dimensional cyclic density spectrum; and a simulation signal is built through the obtained modulation frequency and carrier frequency according to the complex amplitude modulation model, the corresponding detecting result is obtained through processing and compared with the actual detecting result, and thencorrectness of characteristic extracting is verified. Through the method, the fault type of the fan can be detected and judged in real time, detecting is more accurate, and the high practicability isachieved.