On May 26th, at the high-end dialogue on "data security" of China International Big Data Industry Expo in 2019, Academician of the Chinese Academy of Sciences and Chairman of the China Internet Association, He Hezhen, expressed his views on the use of blockchain in data security. It said that the combination of the Internet of Things and the blockchain can solve the difficult problem of small and medium-sized enterprises. It also mentions that although the security structure of the blockchain itself is conducive to solving the problem of data security. However, the blockchain itself uses a credit algorithm. If there is a loophole in the code, it will be attacked by hackers. Therefore, the blockchain itself cannot guarantee 100% security and needs our attention.