Babbitt reported on the 12th, October 20th, 2019 CCF Blockchain Technology Conference was held in Chengdu. Academician Chen Chun of the Chinese Academy of Engineering said in his speech entitled "The Key Technology of the Alliance Chain and the Regulatory Challenge of the Blockchain" that the traditional information system and the blockchain system have certain limitations. On the one hand, the blockchain system needs to pass. The under-chain system expands the computing and storage capabilities; on the other hand, the existing system (under the chain) needs to interface with the blockchain system to solve the problem of information silos, tamper-proof, etc., which requires the data under the chain to be effectively coordinated. Ensure the relevance and consistency of the data under the chain. He also pointed out that data collaboration technology under the chain is an important direction for future development. At present, the research on data collaboration under the chain is just beginning. The related technology research includes side chain and state channel, cross-chain technology, sub-chain computing and chain storage.