Arbitrum is a set of ethereum extension solutions, through Optimisticrollups, Arbitrum can be smart contract execution data compression, efficient packaging uploaded to Ethereum, can achieve high throughput, low cost smart contract, at the same time can maintain the safe L2 protocol without trust. Arbitrum has three modes: AnyTrust Channels (channel), AnyTrust Sidechains (side chain) and Arbitrum Rollup, now for Arbitrum Rollup, has been in the test online line. Arbitrum interacts closely with Ethereum and exposes the same developer interface, so Ethereum developers can easily cross-compile their contracts to run on Arbitrum; These functions of Arbitrum are realized through the unique combination of incentive, network protocol design and virtual machine architecture. Arbitrum Rollup is now the first and only fully functional EVM compatible Optimistic Rollup. On May 29, the Uniswap community approved the deployment of Uniswap V3 on Arbitrum (it was deployed on June 7) with nearly 100% support. On the same day, Arbitrum development team Offchain Labs announced that it has deployed the ethereum main network test version of Arbitrum One, supported by OptimisticRollups, and open to developers.