This paper introduces the working principle of the attitude measuring device for DC power supply circuit. The sensor output filter circuit of DC power supply circuit has been designed based on the working demand of sensitive element in the attitude measuring device. The direct coupling influence on the sensor output from the system power supply, as well as the actual working circumstance in engineering application, has been analyzed. Under the practical engineering application analysis of the circuit, the sensor in the attitude measuring device is able to work normally and avoid the dithering phenomenon of the system in zero position. The working requirements of the system have been well satisfied.