In order to solve the problem of trajectory privacy leakage caused by the collection of numerous trajectory information of moving objects， a dummy trajectory-based trajectory privacy protection algorithm was proposed. In this algorithm， considering the user’s locations under disclosure， a heuristic rule was designed based on the comprehensive measure of trajectory similarity and location diversity to select the dummy trajectories， so that the generated dummy trajectories were able to effectively hide the real trajectory and sensitive locations. Besides， the trajectory directed graph strategy and the grid-based map strategy were proposed to optimize the execution efficiency of the algorithm. Experimental results on real trajectory datasets demonstrate that the proposed algorithm can effectively protect the real trajectory with high data utility.