In the study of the basic theory of the finite state machine and the application of the game development, combined with the actual needs of the emergency simulation training system, solve the system role of state controlling problem with a finite state machine controller components in Delta3D engines. This paper first introduces the basic theory of the finite state machine and the characteristics of the Delta3D engine architecture, designs a finite state machine example and describes in detail the finite state machine controller components of the overall structure,the basic functions and specific implementing way.