This paper investigates the high-power laser-induced damage of two types of single-layer SiO2 thin films on K9 substrate, which are respectively deposited by IBSD technique and sol-gel technique, and have the same substrate parameters and the same film thickness. They were tested by surface thermal lensing technique to obtain the thermal absorbance and the dynamic response. The results show that the laser-initiated damage threshold of Sol-Gel SiO2 thin film is far higher than that of IBSD SiO2 thin film. And combined with threshold measurement and the microscopic observation, this paper well explains in detail the threshold difference between Sol-Gel SiO2 and IBSD SiO2 thin films.