Decentralized finance (DeFi) is an emerging financial model. DeFi projects are built on the basis of blockchain technology. They replace traditional financial institutions through smart contracts and provide users with decentralized financial services such as lending, payments, trading, and earning interest, including providing liquidity to various markets and participating in activities such as earning tokens in liquidity mining. As an important application of blockchain technology, DeFi, with its transparency, lack of intermediaries, and global accessibility, has deposited over 300 billion USD so far in various decentralized financial protocols.