Abstract: A chip access control method is proposed in this paper to solve the file access control problem of multi-applications chip. Firstly, a security state machine is designed, which subdivides the access right into 32 levels. Driven by user instructions, the security state machine undergoes security state transition. Only when the security state meets the preset file access conditions, file access is allowed. At the same time, in order to isolate the access right of different applications, the environment state machine and the application state machine are defined. The environment state machine controls the access authority of the chip as a whole, the application state machine controls the access authority of a single application, and through the combination of two state machines, the fine management of chip file access control is realized.