Blockchain technology is quite suitable to solve the difficulties in the field of education due to its secure and decentralized nature.This paper introduces blockchain's basic theory and key technologies which include the block structure and construction of blockchain,the architecture of blockchain platform,types of blockchain,consensus algorithms and smart contract.Then the new trends in modern education field such as lifelong education and cross-domain education are presented and the limitations of traditional digital education system are discussed.We give detailed description and analysis of the application of blockchain technology in the field of education such as educational data sharing and verification,learning tracing,awarding and shaping of study path,study evaluation,educational management and decision making.Finally the questions in application of blockchain technology in education field and future research directions are summarized.