To address the shortcomings of the previous latitude and longitude based airspace usage and expression methods in terms of precision and dynamics of rescue mission modeling, we propose a rasterized modeling method for forest fire rescue flight airspace. Corresponding to the key points of forest fire rescue such as water sources, flight routes, fire areas, the basic elements of low-altitude rescue flight airspace is designed as point airspace, linear airspace and surface airspace three categories. Based on the GeoSOT grid modeling method, the dynamic airspace model of the airspace in the horizontal and vertical directions is constructed by using a positive hexagonal grid to dissect the emergency flight airspace based on the mean sea level. Design an airspace grid coding system that includes attributes such as grid address, altitude, and use type, which can support the establishment of a dynamic management structure for emergency flight airspace. A forest fire rescue flight operation scenario is used as an example to verify the feasibility of the given airspace rasterization modeling method.