Abstract: Low-alloy high-strength steel Q460 thick plates were welded by CO₂ gas shielded arc welding with solid wire and flux-cored wire at different heat inputs (12.6, 16.4, 19.5 kJ·cm^-1). The effects of welding wire and heat input on the microstructure and tensile properties of the joint were investigated. The results show that the proportion of acicular ferrite in columnar grain zone in weld zone of the two joints decreased and the grain boundary ferrite of large size increased with the increase of heat input. The hardness of weld zone of the joint welded with solid wire changed little with the increase of heat input,but that of the joint welded with flux-cored wire decreased significantly. The yield strength and ultimate tensile strength of the joint welded with solid wire were similar to those of base metal whereas the elongation was lower than that of base metal; the elongation decreased with the increase of heat input. The strenth of the joint welded with flux-cored wire was equivalent to that of the base metal at lower heat input. The increase of heat input obviously reduced the tensile strength, but affected the yield strength and elongation slightly.