Abstract: TA2/3A21/AZ31B three-layer composite plate is prepared by explosive welding. The interface, microstructure and mechanical properties of the composite are tested and analyzed by optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and universal testing machine. The experimental results show that the tensile strength, yield strength and elongation after fracture of the TA2/3A21/AZ31B composite prepared by one-time explosive welding are about 303 MPa, 233 MPa and 9.7%, respectively. The special wavy structures from explosive welding are formed at the titanium/aluminum and aluminum/magnesium interfaces. The thickness of Ti-Al diffusion layer at the titanium/aluminum interface is about 5 μm, and the thickness of the Al-Mg diffusion layer at the aluminum/magnesium interface is about 30 μm. The shear strengths of the Ti-Al and Al-Mg diffusion layers are 132.6 MPa and 116.3 MPa, respectively. Compared with TA2/AZ31B composite, mechanical property of the TA2/3A21/AZ31B composite is greatly improved.