The paper aims to study the algorithm of unit load device (ULD) to solve the economic benefits and timeliness problems of air cargo in the aviation industry of China because the assembly and arrangement of the cargo on the air container is completed manually, and there is no software system to realize automatic calculation. In this paper, the heuristic algorithm was combined with the advanced greedy algorithm and genetic algorithm to study the optimal packing of single unit load device. The packing model was built and the algorithm for a single unit load device (ULD) was optimized, which can make full use of the space saved by the ULD and realize the optimal packing. The loading scheme proposed is more accurate, more stable and more economical than the manual calculation. In the future, it is expected to transform this algorithm into a highly intelligent software system, which will promote the automation and workflow standardization of air freight.