In this paper, we study a multiuser tracking problem in the multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system aided by multiple reconfigurable intelligent surfaces (RIS). A base station (BS) receives the uplink signals from users reflected by multiple RISs and tracks the positions of these users. Considering the users’ mobility and the blockage of light-of-sight (LoS) paths, we establish a probability transition where the geometric constraints between channel parameters and multiuser positions are utilized. An online algorithm is proposed to estimate the multiuser positions, the angles-of-arrivals (AoAs) at RIS, the time delay, and the blockage of the LoS path. Simulation results show that the proposed algorithm can achieve up to centimeter-level tracking accuracy.