In tracking maneuvering target, target state and target motion mode must be estimated at the same time, and parameters or structure of filtering function should be modified according to estimation results, so that it can reduce the difference between filtering function and target motion mode, and increase tracking accuracy of maneuvering target. For overcoming the shortcomings of the present suboptimal multiple model algorithms, a new suboptimal multiple model (MTMM) algorithm is introduced, based on multiple target motion mode distribution. Simulation results show the validity of MTMM algorithm.