To explore a new method to improve the glass cutting quality, the principle of glass laser cutting by thermal stress was introduced. The advantages and the disadvantages of cutting glass by single focused and un-focused CO2 laser beams were analyzed, respectively. A novel method of cutting glass by dual CO2 laser beams was proposed, where a focused CO2 laser was applied to pre-score a line on the glass surface and the other unfocused laser beam was applied to separate the substrate along the scoring line. The cutting qualities with single and dual laser beams were compared experimentally. The results show that cutting glass by dual laser beams is an ideal cutting method, which not only makes the cutting path in a straight line but also makes the cutting profile very smooth.