Abstract: The consensus mechanism is the core of the application of blockchain technology. This paper analyzes various typical technical principles, technical features, application scenarios and selection criteria of the consensus mechanism, and provides reference and suggestions for the blockchain researchers and developers on selecting consensus mechanism. This paper firstly introduces the basic principles of various popular consensus mechanisms and compares the advantages and disadvantages of various consensus mechanisms. Subsequently, the characteristics of various consensus mechanisms are compared from the aspects of performance efficiency, degree of de centralization, and need for tokens. And then, this paper analyzes two common application scenarios of blockchain in real life, and finally puts forward a five-dimensional selection criterion of consensus mechanism

Key words: blockchain, consensus mechanism, proof of work, proof of stake