The Guangzhou Trusted Certification Service Platform completes the trusted authentication docking by connecting to the electronic certification authority of the Hong Kong Post Office, and realizes the access of Guangdong-Hong Kong mutual recognition certificates issued by the electronic certification authority of the Hong Kong Post Office, and the registration and issuance of users and certificates. Hong Kong residents use cross-border certificates to sign electronic documents when setting up businesses, and realize the signing service of blockchain cross-border contracts between mainland resident enterprises and Hong Kong resident enterprises based on the platform. Through the connection of the Hong Kong Post Office's electronic certification authority to the blockchain, the Guangzhou Trusted Authentication Service Platform will register and upload the verified identity information of Hong Kong residents, and can verify the identity and electronic signature of Hong Kong residents based on the cross-border certificate information and identification information on the blockchain. At present, the service has provided identity verification and winding services for 121 Hong Kong residents, signed a total of 468 cross-border contracts, completed 121 user information on the chain, and signed 468 cross-border contract certificates.