Steering engine is an important part of missile guidance and control system. When the missile is in the launcher, rudder is limited by launcher, so rudder can’t rotate. The traditional method cannot realize the steering engine self-checking. Therefore, design a new steering engine self-checking method. The function detection of electric steering engine was achieved by detection and judgment of brushless DC motor’s Hall signal’s phase sequence. The controller of electric steering engine controlled the rudder surface to rotate slightly. The self-checking arithmetic was realized by program in DSP. In the text, Hall sensor brushless DC motor’s style was selected. The self checking circuit and control algorithm were designed. The examples proved that steering engine could be self-checked in the launcher. The method was effective and reliable. The method has good applicability.