The invention discloses a digital certificate and electronic seal system and an implementation method for an electricity trading system. Core confidential data in the electricity trading quotation process are electronically signed and encrypted by a centralized price competition trading encryption implementation method, safety protection measures are provided for the core data, and data safety, confidentiality and undeniable and anti-tamper properties are ensured. Declared prices of users in price competition need to be encrypted by a certificate in the system. The system solves the problems that the price competition data of the users are easily leaked and tampered in a traditional digital environment, bidding data in the digital environment are easily leaked and decrypted in advance, and integration and synchronization are needed in an internal and external net isolation environment.