In view of the Point Spread Function(PSF) for near-field Multiple-Input Multiple-Output (MIMO) radar imaging cannot analyze the scattering mechanism of complex targets effectively, a simulation method of millimeter wave near-field MIMO radar imaging based on near-field Physical Optical(PO) scattering data is studied. The method uses near-field physical optics method to compute the near-field scattering field including the information of array configuration and scattering mechanism. Near-field MIMO image is finally generated by imaging processor. Using the D-band "T"-shaped two-dimensional sparse MIMO arrays to carry out the near-field imaging experiment, the simulation results are in good agreement with the actual imaging results. This method can analyze the imaging performance of the near-field MIMO imaging system, support the formation design, and reveal the near-field scattering characteristics and imaging mechanism of complex targets.