Cold metal transfer(CMT) welding of nickel-coated Q235 steel studs with 6061 Al alloy was carried out using ER4043 as filler metal.The welding process was stable,and appearance of weld formed well without surface defect under the parameters of welding current 121 A,welding voltage 15.4 V and welding speed 6 r/min.The microstructure of filler metal was analyzed by means of scanning electron microscopy.The filler metal and 6061 Al alloy were fused to form fusion welding interface,the fusion zone had a good bonding without any micro defect.The steel stud did not melt and brazing interface was formed between the filler metal and steel stud.Two different reaction layers existed in the brazing interface,the Fe_2Al_5 layer about 10- 12 μm formed near the steel stud side,and the other layer was mainly composed of FeAl_3.Nickel-rich zone was formed in the root toe area of the fillet weld,which was mainly composed of Al_3Ni_2.The tensile tests showed that the maximum shearing strength of the joints was 129 MPa.The joint was brittle fractured in the intermetallic compound layer where plenty of FeAl_3 were distributed continuously. Cold metal transfer (CMT) welding of nickel-coated Q235 steel studs with 6061 Al alloy was carried out using ER4043 as filler metal. The welding process was stable, and appearance of weld formed well without surface defect under the parameters of welding current 121 A , welding voltage 15.4 V and welding speed 6 r / min. The microstructure of filler metal was analyzed by means of scanning electron microscopy. filler metal and 6061 Al alloy were fused to form fusion welding interface, the fusion zone had a good bonding without any micro defect. The steel stud did not melt and brazing interface was formed between the filler metal and steel stud. Two different reaction layers existed in the brazing interface, the Fe_2Al_5 layer about 10-12 μm formed near the steel stud side, and the other layer was mainly composed of FeAl_3.Nickel-rich zone was formed in the root toe area of ​​the fillet weld, which was mainly composed of Al_3Ni_2. tensile test showed that the maximum shearing strength of the jo ints was 129 MPa. The joint was brittle fractured in the intermetallic compound layer where plenty of FeAl_3 were distributed continuously.