Abstract: With the development of automobile industry and the improvement of people’s requirements for driving comfort, it is increasingly important to control and improve the discrete noise level of the cooling fan module (CFM). In the early stage of CFM design, finding a fast method to predict discrete noise is helpful for designers to shorten design cycle and improve work efficiency. In this paper, a combined method of rotor-stator blade phase modulation is proposed to control the harmonic noise of CFM, i.e., to reduce the second and third harmonic in the CFM noise spectrum by controlling fan blade angle distribution parameter of CFM; Based on the “Venetian blind” theory of stator vanes, its angle distribution parameter is designed to further reduce the first harmonic component in CFM noise spectrum, aiming to improve the CFM discrete noise level. The method is verified by experiments in two combined cases of 7-blade fan, 6-vane and 8-vane respectively. And the experimental results are in good agreement with the theoretical prediction results.