The invention discloses a wind tunnel test method for a coaxial double-rotor hub model of a helicopter, and belongs to the field of hub wind tunnel test methods. According to the method, a large-advance-ratio coaxial double-rotor hub model flow mechanism and a pneumatic interference test can be carried out. The method comprises the following steps of firstly, installing a test bed in a wind tunnel, and carrying out coaxial synchronous reverse rotation motion of the model through the test bed; secondly, monitoring a vibration level of the test bed in real time by a vibration monitoring system,and researching dynamic characteristics of the test bed; thirdly, measuring six force factors of the model by a box type balance, measuring a flow field of the model by a PIV flow field measuring system, and measuring the surface pressure of the model by an electronic scanning pressure measuring system or a pressure sensor; fourthly, during a test process, replacing components of the coaxial double-rotor hub model according to the need in order to research the aerodynamic characteristics of the model with different appearances or different flow control modes; and finally, obtaining the aerodynamic characteristics of the model. According to the method, a problem of measurement of the aerodynamic characteristics of the rotating coaxial double-rotor hub model is solved.