In order to obtain the thermal response and melting through characteristics of materials irradiated by high energy laser with airflow environment in field of laser processing and other applications, a physical model considering the mechanisms of heat conduction, convective heat transfer, melting and ablation was constructed by using the approximation of plane heat source and unsteady method. The model was validated by experiments and was used for evaluating quantitatively the thermal responses of material. Then, the temperature rise and penetration law of aluminum alloy plates subjected to different laser power density in airflow were obtained. The results indicate that the melting through time decreases sharply with the increase of laser power density under the same target parameters. And the calculated melting through time is consistent with the results by using the gasification ablation model of thermal balance integration method in the literature. The analysis of perforation time under different conditions shows that the airflow factor has a significant influence on laser ablation melting through when the laser power density is small (approximately around 500 W/cm2). When the laser power density is large (above 1500 W/cm2), the effect of airflow through convective heat transfer is insignificant. In addition, the physical model considered in calculation is close to the actual physical process. Above calculation results and analytical understanding provide a quantitative basis for simplifying reasonably the laser ablation models.