Simplified modeling of the landing gear system can reduce the difficulty of the landing dynamic response, which offers theoretical foundation and reference for the preliminary design of landing gear. Based on the viscoelastic rods technique, the simplified modeling method of diagonal stanchion landing gear system is studied and used to analyze the landing dynamic response with ANSYS/LS-DYNA software. First, based on the landing gear structure and landing status, the simplified dynamics analysis model of the diagonal stanchion landing gear system is established by using the viscoelastic rods technique. The numerical solver program of the differential equations is compiled by MATLAB. By comparing the load curves, the displacement curves and the energy absorb chart, it is shown that the modeling method based on the viscoelastic rods can better simulate the landing dynamic response. The suggested method is valuable for the landing gear preliminary design and the detailed design of connection structures.