In order to make the design of landing gear to fulfill the requirements of the airship criterion FAA-P-8110-2, a methodology of load calculation for landing gear was presented in this paper, which was based on the double-springs' vibration model. In term of the typical theories of dynamics, the differential equations of the system were derived herein. A simulation tool for this model was developed based on Python scientific modules, which was built in visualization and friendly operation. Based on a manned airship, the main factors affecting the load of the landing gear are analyzed, and the reasonable values of the load are obtained by simulation. The results of this paper can be used as the inputs for structural design and strength analysis of airship landing gear.