Collision between the driver of non-motor vehicle and car door often happens when the car driver or the passenger in the parking car opens the door suddenly ignoring a non-motor vehicle passing by. The collision protection system is proposed by installing an airbag in the car door. When the collision accident between the driver of non-motor vehicle and the car is unavoidable, the airbag will automatically deploy to provide head protection for the driver of non-motor vehicle. Utilizing HyperWorks and LS-DYNA, the finite element model of the collision is established to simulate the situations of installing airbag or not with the door on different opening angles (60°, 70°) and to verify the feasibility of the proposed method.