The block chain is the underlying technology of the digital currency-Bitcoin. Block chain is a distributed database system that participates in nodes. It has the characteristics of de-centering and unforgeability
which is highly regarded by the financial world.This paper expounds the advantages of the block chain technology in the network security from the aspects of the technical architecture and key technology of the block chain technology
and puts forward the thinking of the application of the block chain to the security of the IoT
which aims to help the research of block chain technology in the security field of IoT.