Abstract: Multiple-input multiple-output(MIMO) radar has experienced rapid development due to its advantages, such as short imaging time and flexible aperture synthesis directions, prompting extensive studies on related imaging optimization theories. However, the system architecture of MIMO radar significantly increases the cost of imaging verification experiments. In this paper, two platforms of a rail system are used to respectively carry the transmitting and receiving antennas, traversing the element position combinations of the target array to simulate the MIMO radar imaging process. Therefore, a hardware-in-the-loop simulation imaging validation system with reduced complexity and adjustable element positions is established. In addition, to address the issue of echo amplitude being affected by transmission parameters, which leads to the deterioration of target response sidelobes and affects the judgment of imaging quality, an amplitude inverse weighting term is introduced during the imaging focusing process to optimize the back projection (BP) algorithm. Simulation and imaging experiment results demonstrate that the MIMO radar imaging validation system achieves ideal imaging performances within an acceptable error range, possessing imaging quality validation capability. Furthermore, the sidelobe levels of the target response is suppressed by the improved BP algorithm, mitigating the influence of amplitude modulation terms.