Smart contract plays as a very important milestone on the road of evolution of blockchain technology. Blockchain-based smart contracts are decentralized，verifiable，tamper-resistant，transparent，and trustworthy，providing a basic technical guarantee for building a trusted digital world. Current smart contracts also face challenges such as readability，security，deployment correctness，and privacy. To build a secure and trustworthy smart contract system，we need to start from the programming language，formal verification，and running environment of the smart contract to ensure the security and trustworthiness of the smart contract throughout its life cycle.