A dynamic model for overload of landing gear due to elevator platform dropping is proposed. Mathematical formulations for mechanical properties of shock strut and tire are given for large loading conditions. Numerical simulations are applied to study overload of landing gear in elevator platform dropping. Mechanical mechanism of large overload of landing gear due to elevator platform dropping is analyzed. If the elevator platform drops freely from different height， the comparative increment of overload of landing gear caused by wheel mooring is no more than 10%. However， in a case of wheel mooring， the negative amplitude of overload within tension period will be much larger than the positive overload within compression period.