Wafer mark is very important on both process management side and wafer history track. Glass wafer used for R&D lab does not have mark before process. Some labs make mark by using diamond material manually,and this will have disadvantages such as crack and excess mark depth,which affect the following process step. The glass wafer was marked by using 10640 nm CO2 laser. During the work,the effect of laser average power,pulse frequency and scan speed on mark definition was studied,and crack and mark height were observed by eye inspection,metalloscope and 3D optical profiler. The results show that the effect of pulse frequency on mark definition,crack and mark height is not obvious;the average power is proportional to mark definition and mark height,and is irrelevant to crack;scan speed is inversely proportional to make definition,crack and mark height. Under the condition of 40% average laser power,20 kHz pulse frequency and 150 mm/s scan speed,there are clear definition,non crack and 185 nm in height glass wafer mark. The overall result shows that the proposed method is robust.