Abstract: As a low-cost and easily deployable channel environment control node, the Reconfigurable Intelligent Surface (RIS) can effectively detect, locate and identify blind spot obscured moving targets, and has significant application value in fields such as intelligent driving. Ris-assisted Multiple-Input Multiple-Output (MIMO) - Frequency Modulated Continuous Wave (FMCW) radar system This paper conducts research on the measurement of distance and speed of non-line-of-sight targets. Firstly, construct the transmission and reception signal models of the RIS-assisted MIMO-FMCW radar system in non-line-of-sight scenarios. Secondly, an Alternating Direction Method of Multipliers (ADMM) algorithm based on the criterion of maximizing path gain is proposed to optimize the parameters of the RIS phase shift matrix; Then, the radar signal is processed, and the distance-Doppler spectrum of the target is obtained from the original radar echo, thereby obtaining the distance and velocity information of the non-line-of-sight target. Finally, the simulation results show that the proposed method can effectively estimate the distance and velocity parameters of non-line-of-sight targets, providing a strong guarantee for target detection technology in non-line-of-sight areas.