Objective: To prevent the occurrence of up-coding behavior，it explored the doctors' coding process and the effects of medical insurance departments' supervision on patients. Methods: The evolutionary game model of doctors' and health insurance department's behavioral strategy choice was established and analyzed by Matlab simulation to obtain the strategy stability points of both sides of the game for various situations. Results: The benefits of doctors，rewards and punishments of superior departments，and the cost of supervision will affect the strategy. Conclusion: The evolution of gaming subjects to the direction of "normal diagnosis and strict supervision" could be promoted by reducing relative returns，enhancing incentives and penalties，and introducing scientific supervision systems.