Balsaming lens will be damaged when irradiated by laser of certain power. The model of one-dimension unstable temperature field during the interaction between multiple-pulse laser and material is established, and the transient temperature distribution of glass material of balsaming lens is calculated. The fusion moment and the moment when cementing material melts are researched by means of numerical calculation. Experiments about damage in several balsaming lenses of the same kind irradiated by multiple-pulse CO2 laser, the parameters of which are 10Hz, 200ns and 20WM, are carried out. It is found that when the irradiation time reaches 12s, the front surface of balsaming lens is molten. When the irradiation time reaches 30s, colorized dapples are suddenly formed in the cementing layer of samples. It indicates that cementing material is intenerated and balsaming lens is thoroughly damaged. The result of theoretical analysis exhibits good agreement with the experimental result.