Abstract: Ground-based MIMO (Multiple-Input Multiple-Output) imaging radar is a new kind of radar that has broad application prospects in geological disaster warning such as landslide. It has the advantages of good portability, freedom of motion compensation and high image frame rate compared with the traditional ground-based synthetic aperture radar. When using multiple MIMO radar systems for three-dimensional deformation monitoring, the bistatic MIMO radar configuration can effectively supply the traditional monostatic observation and greatly improve the overall observation degree of the system. However, there is no effective imaging performance evaluation method for bistatic MIMO imaging radar now. Aiming at solving this problem, this paper analyzes the spatial resolution property of bistatic MIMO imaging radar by generalized ambiguity function. Firstly, the expression of generalized ambiguity function and equivalent array for ground-based bistatic MIMO imaging radar is derived according to the geometry of the system. Then the side lobe’s direction, two-dimensional resolution of the system and the position of grating lobes are analyzed according to the generalized ambiguity function, and the spatial resolution of the system is derived. The correctness of the calculation is finally verified by two Matlab simulations.