Blockchain as an emerging information technology has developed rapidly in recent years. Its technical features complement each other with the basic characteristics of Industrial Internet of Things (IIoT). Applying blockchain to IIoT can not only fully express the application value of blockchain, but also provide improvements in the IIoT field greatly. In this paper, we present a research of blockchain technology in the aspects of basic concept, technical architecture and development. Then, this paper discusses about IIoT for Industry 4.0. Moreover, we analyze the fit degree of blockchain with IIoT, and put forward the integrated system architecture. Finally, the future directions and challenges in the development of IIoT integrated with blockchain are prospected, so as to provide reference for theoretical research and application in this filed.