In plane lapping, workpiece material removal and lapping wheel wear has been influenced each other and should be evenly distributed. Only required a flat lapping wheel, it could be obtained with flat workpieces and small thickness deviations. Therefore, the choice of the truing operation has an important effect on the quality of the lapping wheel and on the flatness of product. This is a way that using truing ring to true lapping wheel in certain eccentricity plane lapping system to acquire the flatness. The kinematics of certain eccentricity plane lapping for uniformity of processing is analyzed in this paper firstly. Then different sizes and locations of truing ring that influences truing on the flatness of lapping wheel has evaluated and simulated. Lastly, a suitable truing operation of certain eccentricity plane lapping is proposed.