With the rapid development of power big data and intelligence, the complexity of intelligent distribution network is getting higher and higher, and the accompanying data security problems are also increasing, which seriously affects the healthy development of intelligent distribution network. In order to solve the problem of data security in power distribution network, this paper improves the Paillier encryption algorithm based on Chinese residual theorem and CRT system enhanced decryption technology, and analyzes the effectiveness of this algorithm by comparing examples. The results show that the improved Paillier encryption algorithm proposed in this paper can better fuse the communication security data of the distribution network, and has high operational efficiency and low communication load, which can meet the data security protection requirements of the intelligent distribution network, and has good practicability and economy.