In order to solve the problem that the low efficiency of traditional frequent patterns mining algorithm, an improved Apriori algorithm based on FP-tree is proposed. Firstly, the join preprocessing process is added to the join step of Apriori algorithm. Secondly, the CP-tree is extended to construct a new tree structure, ECP-tree. The new tree structure can construct a compact prefix tree with only one scan of the database, and support interactive mining and incremental mining. Then, the improved points are combined with the APFT algorithm for mining frequent patterns. Finally, experiments are performed using two datasets in the UCI database. The experimental results show that the improved algorithm has higher mining efficiency and the frequent pattern mining speed is significantly improved.