Abstract: Although the interface has the features of melt, and pressure welding in the mean time,the seam and "hole" brought by the melt weaken the bonding strength of interface greatly,and the effect of melt on interface must be eliminated in explosive welding, so the conventional molten mechanism of explosive welding is negated.The diffusion welding is a kind of form of pressure welding,and the diffusion is not the reason of the bonding of interface but the result of interface high pressure.So the diffusion welding cannot also explain the bonding mechanism of explosive welding.The experiment and theory make it clearly that explosive welding is a special pressure one.In order to get good interface of no melt, explosive charge must be selected on the low limit of welding windows.