Silver electrode layer of piezoelectric ceramic transducer requires good surface quality and high efficiency. Efficiency of traditional lapping and polishing is very low. Ultra-precision grinding technology is also unsuitable for the thickness of workpiece is extremely thin. Semi bonded abrasive lapping is a new ultra-precision processing method. The new ultra-precise method can achieve good surface quality in short time, and removal stock of workpiece is small. In order to research the optimal technology of semi bonded abrasive lapping about silver electrode layer, this paper research several major processing parameters by experiments. The results show that appropriate processing load can obtain better surface roughness of silver electrode layer，and surface roughness of silver electrode layer has little change with different processing speed. By using ultra-fine semi bonded abrasive plate, 94.08KPa processing load and 40 rpm polishing speed, after 30 minutes, surface roughness of silver electrode layer is 11nm, and removal stock is 11.5μm.