The screw axial movement error is one of the most important factors which affect the transmission accuracy of screw drive.It is discovered that the screw axial movement error appeared to a cyclic variation.The formula for calculating maximum error of the screw axial movement is Δmax=Dtanαmin.The related literature hasn’t analyzed why αmin is minimum.The form and position error in the screw drive affecting transmission accuracy is analyzed under three cases
and the formula for calculating maximum error of the screw axial movement is completed and perfected.