Based on the grain movement model of ultrasonic grinding, models representing the grinding force of single abrasive and the material removal rate (MRR) are deduced and verified. Mechanism of high efficiency material removal in work lateral ultrasonic vibration grinding (WLUVG) was analyzed. The MRR of fine-crystalline ZrO2 ceramics in WLUVG and conventional grinding (CG) with diamond wheel were researched experimentally in this work. The effects on the MRR, the surface roughness and microstructure of the process parameters and the size of abrasive are measured. It has been concluded that: (1) the MRR in ultrasonic grinding process is two times as large as that of in CG. (2) any increase in the amount of energy imparted to the workpiece in terms of the average diameter of grains, grinding depth both in with and without ultrasonic grinding, will result in an increase in the MRR and the surfaces roughness. (3) the ultrasonic grinding surface had no spur and build-up edge and its surface roughness was smaller than CG significantly. Surface quality of vibration grinding is superior to that of CG, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile mode grinding.