Fourier telescopy (FT) is a sort of high-resolution imaging technology, which integrates laser initiative imaging technology, optical synthetic aperture technology and phase close technology. The effect of frequency shifting of laser is one of the most important factors to influence imaging quality of the FT system, especially in the situation of high power, broad beam and large modulation bandwidth. Various frequency-shifting error models are proposed, the transfer function of error in system is built, the effect of which on imaging of the system is researched by simulation, error analysis results of the various models are obtained. According to the results, the image quality of the system is directly influenced by the frequency shift accuracy and stability, the value of Strehl between the inverted image with error and the theoretically inverted image is below 0.2 in some of the models. As indicated, the reasonable design of acousto-optical frequency shifter and the driver circuit is an important way to improve the imaging of the system.