Driven by the carbon peaking and carbon neutrality goals of China, the digital transformation of the energy industry is imperative. With the application and development of blockchain in the digital transformation of the energy industry, the concept of energy blockchain has gradually formed a consensus. Energy blockchain is a new industrial form of the deep integration of the blockchain technology and the energy Internet, which can facilitate efficient collaboration between energy entities and provide technical support and services for innovative business models such as green and low-carbon business. The large-scale development of energy blockchain is inseparable from the breakthrough of multi-level cross-chain technology, but the cross-chain service of energy blockchain still faces many problems. This paper divides the current research status of energy blockchain into five categories, namely energy blockchain architecture, smart contract applications, cross-chain technology, blockchain node management and blockchain privacy protection, and we summarize the related research work in these five directions respectively, sort out the principles, advantages and disadvantages of each research scheme in detail; then, in order to promote the development of the cross-chain service security technology of the energy blockchain, we combine the supervision mechanism and the consensus mechanism to propose a multi-level cross-chain collaborative supervision of the energy blockchain architecture, according to the actual needs of the energy blockchain; finally, we summarize problems that need to be solved in the energy blockchain cross-chain service security technology, and put forward the research prospect of blockchain in the energy field.