Laser damage threshold value of high-quality CVD freestanding diamond films is investigated by CO2 CW2 laser. The damaged diamond films are characterized by SEM and Raman spectra. The results show that high-quality CVD freestanding diamond films have higher laser damage threshold value, its value changed from 1. 15 ×106 to 2. 26×106 W / cm2. The laser damage of diamond film is because of thermal shock damage, itsmechanism is thermo-force coup ling