Blockchain is a new technology that establish trust. It is considered as the fourth industrial revolution in human history，and will potentially change the way values are transmitted in society. As the basis of trust is the effective protection of data and privacy. In this article，we explore and research on the technology to enhance privacy protection from the perspective of data protection on blockchain. We present the analysis of methods and strategies of data protection on blockchain，in respect of blockchain architecture，storage，transmission，transaction，and tripartite authentication. Finally，we analyze the pros and cons of data protection on the blockchain comprehensively and discuss the future outlook.