Abstract: Observing the movement pose of the flying plate by X-ray,the action course of explosive loading and flying plate was obtained.And a new principle was put forward that the bending moment of explosive loading should be greater than the dynamic yield strength moment,and smaller than dynamic tensile strength moment of flyer plate materiel.The upper and lower limit of the thick of explosive charge are given as the weldability window of the thick of explosive charge.The window is useful and advantage for engineering of explosive welding,and ensures the good welding of crisp materiel plate.On the base of the weldability window,the lower limit principle is put forward about the thickness of explosive charge in explosive welding.The explosive charge is reduced 30%,and the quality of the interface is improved for cladding plate.