Aiming at the current practical problem that the calibration precision of ground test equipment of sensors is inconsistent with the design value, a design scheme for a precision adjusting mechanism is presented with high resolution, high stability and five degree of freedom, in order to meet the higher precision application demand of ground calibration of optical attitude sensors. At first, the influence of conformity error of optical axis on position error of star point is analyzed. With a combination of the technical indicators of attitude sensors, we adopt the independent control method of stacked adjusting hierarchy. Then, the gap elimination method is determined according to the gap form within the mechanism. Besides, an adjusting mechanism structure meeting the calibration requirements for sensors is designed. After that, statics analysis and modal analysis are carried out. Simulation results and test data show that the actual measurement displacement resolution of the adjusting mechanism is better than 0.1μm, and the angular resolution is 0.1 second of arc. During the stability test of star point position, star point position error decreases more than 5″compared with the error value in the test which adopts conventional adjusting mechanisms. It may reduce the influence of conformity error of the optical axis on the calibration precision of sensors and improve reliability of calibration results.