The Energy Internet has become a hot topic for the integration of sustainable energies. However, as a result, there are numerous sustainable energy forms and participants, the system is extremely complex, and some key issues are difficult to overcome, such as the control and management of distributed sustainable energy forms. On the other hand, blockchain technology consists of distributed data storage, peer-to-peer transmission, a consensus mechanism, encryption algorithms, and smart contracts. Applying the technical advantages of the blockchain to the Energy Internet can solve many of the problems that hinder its development. The purpose of this paper is to review the development of blockchain and the Energy Internet, and provide some references for the possible applications of blockchain technology to the Energy Internet. Firstly, the definition and characteristics of blockchain and the Energy Internet are introduced in detail. Secondly, the compatibility of the two is analyzed. Then, several application scenarios of blockchain in the Energy Internet are put forward. Finally, the challenges that still exist when applying the current blockchain technology to the Energy Internet are analyzed.