Synthetic aperture sonar has an important application prospect in ocean resources exploration. The SAS receiver antennas generally have multi-aperture configuration, which lead that it is more difficult to obtain the analytical solution of the two-dimensional spectrum. In this paper, the analytical solutions of the multi-aperture SAS with two methods of displaced phase centre antenna (DPCA) and four-order the method of series reversion (MSR) are given respectively, and the phase errors and the imaging results of the two methods under the same conditions are compared by computer simulation. The results of the computer simulation show that MSR has a smaller phase error than the DPCA at the same squint angle, and the DPCA and MSR methods have the same image quality in the small squint angle, but the quality of MSR is much better than that of DPCA in the medium squint angle.