In order to enhance the security and reliability of the payment system, an intelligent payment system under blockchain technology was designed. This system leverages the decentralized and distributed ledger nature of blockchain to provide a more secure and transparent payment solution. The system combined blockchain technology, state secret algorithm and payment system to provide a more secure guarantee for the traditional internet payment system. The point-to-point characteristics of blockchain technology was used to solve the problems of payment efficiency, data security, etc. With the help of big data technology of internet, credit rating was provided to users and credit services are provided. Using trans-chain technology, the data of different blockchains can be shared to figure out a better solution to the liquidity of funds. Compared with Bitcoin, Ethereum and other electronic money systems, the system has achieved a balanced development in terms of security, transaction throughput and transaction delay, which has improved the performance of all aspects to a certain extent, and can better meet the application needs in the current environment.