A modeling method of a steering system for a vehicle comprises the steps of interpreting a coupled relation between an upper tube and a lower tube comprising a steering column, interpreting a coupled relation between the upper tube and an upper bracket and a coupled relation between the lower tube and a lower bracket, and interpreting the movement of a bearing mounted between a steering axle and a steering column using a cylindrical coordinate, thereby improving credibility relative to the interpretation result of a model When the interpretation result is applied to an actual vehicle, the impact absorption capacity and idle vibration capacity are greatly increased, thereby improving the performance of the overall steering system and ensuring safety to the occupants of the vehicle.