The SPH-FEM coupling algorithm was applied to simulate four typical explosive composite combinations including titanium-steel, stainless steel-steel, copper-steel and titanium-aluminum. The ranges of strain rate applicable to the Johnson-Cook strength equation and the Steinberg-Guinan strength equation were analyzed theoretically. Besides, the effects of the thickness of the flyer plate and base plate, impact velocity and impact angle on the temperature, pressure and microstructure of the interface during explosive welding were investigated. The growth mechanism of the interface wave, vortex and a small amount of splashing molten blocks were explored through numerical simulation. Results show that the interface temperature, pressure and waveform size increase with the rise in flyer plate thickness and impact velocity, while the peak of interface pressure decreases with the increase in impact angle. The change in the thickness of the base plate cannot directly affect the temperature and pressure of the interface, where the material behaves as an incompressible liquid and reciprocates, producing sinusoidal waveforms, vortex, and splash molten blocks.