Abstract: Blockchain technology has received extensive attention in the financial field due to the bitcoin system it supports. It has also gained some applications in the field of energy and power. This paper introduces the basic principle of blockchain, and summarizes four main characteristics of decentralization, immutability, scalability and distribution of blockchain technology.According to the difference between the served objects and managed objects, the application of blockchain technology in the power system environment is divided into three attributes（physical, financial, and social） and six functions（information security,monitoring and analysis, trading platforms, contract execution, intelligent decision-making and behavior management）. The problems and technical principles of various functions are analyzed, and a typical scenario is selected for each of the six functions.For large-scale system applications in the power system, two sets of blockchain architectures are proposed: smart dispatching system based on fog computing and side-chain structure, and carbon emission and green certificate trading system based on notary mechanism. Finally, this paper summarizes the bottlenecks faced by blockchain technology to be applied in the power system, and proposes some solutions.