Abstract: In order to solve the problems of data tampering and privacy leakage in the transmission, storage and sharing of traditional electricity meter data, this paper studies the privacy protection method of power grid data based on blockchain. The blockchain technology is combined with Paillier homomorphic encryption method for data privacy protection and sharing the data, and data is directly encrypted at the smart meter side to prevent maliciously eavesdropping. The ciphertext of power data in the station area is gathered from the smart terminal in the area and then uploaded to the cloud. In the transmission process,the data ciphertext is hashed after the chain stores evidence to prevent data tampering. In order to improve the computational efficiency of the encryption and decryption process, the Chinese remainder theorem is used to decompose the modular exponent operation of the original algorithm. After testing, under the premise of meeting the security, the encryption and decryption calculation efficiency of different key lengths can be improved by 50%～75%, which can meet the requirements of dynamic pricing, electricity bill settlement,abnormal analysis and other operations requirementswith directly using ciphertext data in the edge.