Abstract: Explosive welding was applied to prepare TA2/Q235 steel composite plates. The reasons of cracking at the end of the composite plate were analyzed by optical microscopy and scanning electron microscopy. The results show that transition layer formed on the interface of end-cracking zone, and crack appeared in the inside of interface and Q235 steel substrate. Ductility deformation appeared at both sides and end of titanium plate, the ductility part was 5-8 mm beyond original length. Softening of titanium plate during explosive welding was the internal cause for the end-cracking and tension stress wave at the end of composite plates was the external cause.