Abstract: The butt welding of 5083 aluminum alloy and 304 stainless steel was carried out by the cold metal transfer (CMT) twin fusion brazing process. Under the condition of ensuring good weld formation, the influence of welding heat input on the intermetallic compound (MC) layer thickness and tensile properties of the joint was studied and compared with that of the CMT single fusion brazing joint. The results show that the heat inputs of CMT twin and single fusion brazing joint weld to obtain good forming quality were 213.8-486.0, 379.6-590.6 J·mm^-1, respectively. IMC at the interface of CMT twin and single fusion brazing joints was FeAl₃ phase. With increasing heat input, the thickness of IMC layer of CMT twin or single fusion brazing joints increased, and the tensile strength decreased. The minimum thickness of IMC layer of CMT single fusion brazing joint was 9.59 μm, and at this time, the joint had the largest tensile strength of 76 MPa. The minimum thickness of IMC layer of CMT twin fusion brazing joint was 3.36 μm, and at this time, the joint had the largest tensile strength of 109 MPa.