Azimuth resolution of Synthetic Aperture Radar(SAR) is closely related to the trajectory of platform. For the missile-borne SAR, its terminal guidance trajectory not only satisfies with SAR imaging constraints, but also satisfies with the capability of striking front target. In order to acquire the best azimuth resolution within a fixed time, direct shooting method is used in two-dimensional trajectory optimization of SAR terminal guidance. Firstly, optimization model of missile-borne SAR terminal guidance is established, that is, missile command acceleration is as optimal variables, minimum dwell time is as object function. Expressions of object function, imaging constraints, overload constraints are given in detail. Secondly, control variables is discretized to using direct method to convert the optimal control problem into a nonlinear programming problem. Lastly, sequential quadratic programming method is used to solving the nonlinear programming problem. Simulation results demonstrate the validity of the method.