Abstract: In order to obtain the fan audio signals of turbofan engine at the noise measurement point during aircraft take-off in a fast and low-cost way, the synthesis method of the fan audio signals is studied and an audio signal synthesis method based on Heidmann fan noise prediction model is proposed. Firstly, environmental parameters, dimension parameters and performance parameters of the fan components of turbofan engine are input into Heidmann prediction model to obtain source noise data. Then, flight track data are calculated according to ANP database. Then, the source noise data are modified according to flight track data to obtain noise data at the flyover noise measurement point in noise airworthiness certification. The above data are input into Adobe Audition software to synthesize tones and broadband noise by using additive synthesis and subtractive synthesis, and then combine the noise in the software to obtain the audio signal of fan components in flying. Finally, the synthesized audio signal is broadcasted and measured by acoustic measuring instrument, which proves that the method is correct and effective.