Abstract: Four patterns with the same surface area were etched by laser irradiation on the surface of Si₃N₄ ceramics to improve the machining precision. The surfaces with etched patterns were then ground by using diamond grinding wheels, and the effect of pattern form on grinding effect was studied, as well as the effects of wheel speed and infeed speed on grinding force. The results indicate that laser irradiation could produce grooves on Si₃N₄ surface, where the grinding fluid are easy to enter, and that it also reduces the strength of surface Si₃N₄ and then the grinding force decreases up to 63%. Meanwhile, the wheel wear is alleviated. The influence laws of wheel speed and infeed speed on grinding force are the same with those when grinding normal Si₃N₄.