For the imaging application based on the MIMO array in near-field condition， the sparse array design method is researched. Starting from the radar imaging model in near field， the mathematic model of the sparse MIMO array design method based on the back projection （BP） imaging method is deduced， the theoretical expression of the point spread function （PSF） is derived and the suppression performance of side lobe is analyzed. Two sparse array design methods are given for multiple targets imaging verification at the same time. It can be seen from the simulation results that the designed sparse MIMO array can meet the needs of near field imaging and provide a foundation for real application.