With the development of the Internet of things, the privacy protection of the IoT has attracted people's attention, and access control technology is one of the important methods of privacy protection. The IoT access control model is based on the concept of a central trusted entity. The decentralized blockchain technology solves the security risks brought by the centralized model. This study proposes three issues that must be resolved according to the characteristics of the IoT environment. These three issues are:(1) IoT terminal device lightweight; (2) IoT has a large number of terminal nodes; and (3) dynamic issues under the IoT. Then, using these three issues as the core, it is analyzed and summarized that how the mainstream access control model in the existing IoT and blockchain-based access control model solves these problems. Finally, two types of blockchain access control models and the advantages of using blockchain for IoT access control are summarized, as well as the problems that need to be solved in the future for blockchain and IoT access control.