Smoothing is a convenient and efficient way to restrain middle spatial frequency (MSF) errors. Based on the experience, lap diameter, rotation speed, lap pressure and the hardness of pitch layer are important to correcting MSF errors. Therefore, nine groups of experiments are designed with the orthogonal method to confirm the significance of the above parameters. Based on the Zhang’s model, PV (Peak and Valley) and RMS (Root Mean Square) versus processing cycles are analyzed before and after smoothing. At the same time, the smoothing limit and smoothing rate for different parameters to correct MSF errors are analyzed. Combined with the deviation analysis, we distinguish between dominant and subordinate parameters, and find out the optimal combination and law of various parameters, so as to guide the further research and fabrication.