The material removal rate of the lapping process is affected by many factors such as abrasives, lapping fluids, and workpiece materials. The component processing method is used to decompose the factors affecting the material removal rate item by item, and the experimental study on the lapping of abrasive sapphire is conducted to analyze the influence of mechanical, chemical and their coupling effects on the material removal rate. The results show that the material removal rate can be effectively enhanced by the mechanochemical coupling under the action of grinding fluids, and the contribution of the coupling effect to the material removal rate can reach 34.18%. The material can be removed by resin matrix of fixed abrasive pad due to contact friction. However, its contribution to the material removal rate is about 5%.