Abstract: Since it is difficult to obtain the bistatic synthetic aperture radar 2D spectrum precisely, microincrement algorithm is proposed based on Taylor expansion. An approximate highorder point of stationary phase is derived by solving the microincrement between the loworder and highorder point of stationary phase on the basis of the loworder point of stationary phase, and then achieve the 2D spectrum. Microincrement algorithm avoids solving the equation of stationary phase and has a small computational cost. The link between microincrement algorithm and method of series reversion (MSR) is given in detail. The simulation experiment shows that the algorithm has a good focusing performance and accords with the exact transfer function (ETF) algorithm and the method of series reversion, which verifies the effectiveness of microincrement algorithm.