As the yaw angle of a machine-ruling grating will decline its wavefront quality and influence grating performance and application level, this paper proposes a correction method of single piezoelectric actuator according to the characteristics of the grating machine-ruling process. The method adjusts continuously the displacement of a micro-positioning table to correct the yaw angle error of grating line. Firstly, a real-time displacement correction formula for the micro-positioning table was deduced. Then, the yaw angle of micro-positioning table was measured and analyzed by three interferometers and its main component. Finally, amplification and correction experiments of the yaw angle of grating line were performed. The results show that experiments have basically achieved the expected results. Comparing to the result before yaw angle correction, the corrected yaw angle of grating line for a grating with a width of 10.4 mm and linear density of 600 line/mm has reduced by 64% or more. It concludes that the single piezoelectric actuator approach to the yaw angle correction of grating line effectively reduces yaw angle of grating line and improves the quality of the grating. This method is applicable to the yaw angle correction of machine-ruling grating with a large area.