It has been found that the accuracy of particle filtering is much lower when the maneuvering target tracking process has been executed for a long time. The reason for this problem is that the diversity of the sampled particles is rapidly lost because of the excessive resampling. Therefore, the track of the maneuvering target estimated by the particle filtering will be widely wiggly from the true one. Through the research of the distribution of the sampled particles, a new algorithm was proposed. And a detected threshold was set to detect if the particle was dried up badly. When the particle was dried up badly, the particles of the state-space would be reset to relax the degree, so the new particles could contain more distribution information. The new algorithm has a high capability in the simulation of the 2-D maneuvering target tracking.