A novel explosive welding method was proposed to prepare the indium/iron composite plate by inserting a velocity-control plate between the explosive and composite plate to achieve the ideal welding condition. The experiments were conducted to investigate the effects of explosive load, and the parameters of explosive welding were calculated by the theoretic method. Numerical simulation of the smoothed particle hydrodynamics (SPH) method was used to verify the parameters and to investigate the formation mechanism of the bonding interface. The distributions of pressure and plastic strain were also studied. Results show that the wave structures become more obvious when the explosive thickness increases. The shear test results indicate that the shear strength of indium/iron composite plate is 16 MPa, which is higher than that of the indium material. After the three-point bending test, no cracks can be observed at the bonding interface. The modified explosive welding method can effectively prepare the high quality indium/iron composite plate.