The paper reports the experimental results of CO2 laser and Er: YAG laser making holes in myocardium. It gives three experimental curves: h-t curve of CO2 laser's making hole in myocardium when power is 100 W, h-W curve of CO2 laser's making hole in myocardium when irradiating time is 0. 3 s, h-n curve of Er: YAG laser's making holes in myocardium when pulse energy is 500 mJ. It analyses the experimental results and provides a reference for clinical application of laser transmyocardial revascularization.