As a distributed ledger technology, blockchain has evolved into a complete storage system relying on logical control functions such as smart contracts. With the innovation of blockchain technology to the third stage (Blockchain 3.0), smart contracts, as an important component of it, have expanded their application fields from finance to the Internet of Things, government agencies, administrative management, supply chain, and other fields, and have achieved application implementation. This paper is a compilation and analysis of the relevant content on the application research of smart contract technology in blockchain 3.0 stage. Summarized the research status of smart contracts in supply chain and finance, and organized the application of vulnerability detection, data on chain storage, and algorithm design based on smart contracts. The purpose of the article is to summarize the current research status of smart contracts and provide reference for other blockchain research teams, accelerating the practical application process of blockchain technology.