Abstract: The delivery of flight parameters to pilot becomes more and more depending on the graphics display while the modern cockpit display system is tending to be synthesized.The display of compass which requires no distortion,no flicker,and no section is one of the most important pictures in the modern cockpit display system.This paper takes some software measures on the realization of the compass display.It presents a high-speed algorithm of antialiasing rotation of the moving lines,which may be used not only in cockpit display system,but also in all situations demanding some speed of lines movement.