This paper compares the impact of laser direct etching and water jet assisted laser etching on Al2O3-SiC composite ceramics, and discusses the effects of the velocity of water jet on the shape and removal amount of groove. The results show that: The processing method of water jet assisted laser etching can greatly reduce the molten slags of groove, and decrease the thickness of recast layer efficiently, the quality of groove can be improved obviously; Within a given range, the velocity of water jet becomes bigger, the shape of groove becomes more accessible to standard V-groove; When the velocity of water jet increases continuously, the loss of laser energy is more and more, which makes the removal amount of groove become small progressively.