Abstract: The existing imaging algorithms for the multi-aperture synthetic aperture sonar (SAS) cannot obtain a good imaging result in the moderate squint case, because they do not take the aperture dependence of the "non-hop-go-hop" hypothesis and the receiver dependence into account. In this paper, a range Doppler algorithm (RDA) based on the method of series reversion (MSR) is proposed for the moderate squint multi-aperture SAS. Firstly, the aperture dependence of the "non-hop-go-hop" hypothesis is taken into account in the imaging algorithm, the exact range history is expanded by the Taylor series expansion at the beam center to obtain the approximated range history, and the analytical expression of the two-dimensional spectrum of the narrow band signal corresponding to the approximated range history is obtained by MSR. Secondly, the signal of each receiver is processed separately with the MSR based RDA to remove the receiver dependence, then the imaging results of different receivers are added coherently together to remove the azimuth aliasing and to reconstruct the image without losing resolution. Finally, the validity of the proposed algorithm is verified by simulation comparison with the exiting algorithm.