In order to improve the system reliability, and ensure the aircraft and the safety of the pilot, design one unlock control and state detection system of missile rudder face based on DSP. Analysis of the unlock control and lock state detection circuit design and performance analysis of the circuit simulation, to complete the components contained in the system parameter error on system performance. The main failure mode system in common, is proposed to improve the system reliability improvement program. The results show that: though the control signal under strong interference, +27 V power supply is not greater than the instantaneous power down to 2 ms, the gain drift transistor under the condition, that the scheme can make it work.