A method for implementing a smart contract based on a blockchain, a device, and a medium are provided. The detailed implementation includes: creating a resident process for a resident smart contract and creating a virtual machine by the resident process when achieving an enable condition of the resident smart contract; loading codes of the resident smart contract into a memory through the virtual machine; receiving a data access request generated by a normal smart contract within a block generation cycle through an across-contract calling interface of the virtual machine; and executing the resident smart contract through the virtual machine to process the data access request and returning a data access result to the normal smart contract.