Abstract: The effects of the addition of interfacial additives on the microstructure and mechanical properties of liquid-liquid bimetallic composites were studied by means of metallographic observation, scanning electron microscopy,energy spectrum analysis, hardness testing and room temperature stretching. The results show that, the addition of interfacial additives can effectively reduce the oxide defects in the interface of bimetallic composites and the iron and steel materials near them which make the metallurgical diffusion layer of bimetallic interface wider and ease the transition of composition and hardness. The tensile strength of the interface of bimetallic composites increases from 320 MPa to more than 530 MPa. The increase of interfacial strength is related to the cleaning and reduction of bimetallic interface by interfacial additives.