Abstract: In harsh environment, the precision measurement of the axis angle is critical for the development of space system. The factors such as temperature variations and platform vibration severely limit the accuracy and life time of axis angle measurement device in space. The mechanisms to introduce error code and cause the aging of the device in space were analyzed, and a new solution to realize the high precision measurement of axis angle under the complex space environment was proposed based on such analysis. By using a new adaptive technology of encoder signal processing, the shortcomings of traditional processing method used in measuring the axis angle can be overcome. The experiment results show that the resolution of the angle measurement is 0.618″and the peak-to-peak value of the angle measurement error is 6.2″.