Abstract: The block chain technique has become a trend topic in recent years.The prospect of block chain application is highly valued and widely concerned by governments, research institutes and enterprises. It is considered the fifth disruptive inno vation in computing after mainframes, personal computers, the Internet, mobile/social networks. It is the fourth milestone in the evolution history of human credit, after blood credit, precious metal credit and central bank paper credit.With the development of technology, block chain applications and projects emerge in endlessly, and its security problems cannot be ignored. In recent years, security incidents in this filed has been increasing day by day, resulting in serious consequences and economic losses of hundreds of millions of dollars. This paper survey on the security risks faced by block chain technology from multiple perspectives and explores the security testschemeof block chain technology.

Key words: block chain, block chain security, BCSEC