We investigated the effect of dual-beam energy ratio on the microstructure and properties of Q355ND steel laser-metal active gas (MAG) hybrid welding joint. Here, the Q355ND steel was welded using high-power dual-beam laser-MAG hybrid welding. Subsequently, we analyzed the effect of laser energy density distribution on weld cross section forming, weld penetration depth, and weld width by adjusting the energy ratio of dual-beam and obtained the well-formed butt joint of 27 mm thick plate Y-type single side welding. Furthermore, we analyzed the microstructure and distribution of the main elements of the welding seam, weld zone, and heat-affected zone, and measured the microhardness of the welded joint. Results show that the weld penetration depth first decreases and then increases with increasing laser energy ratio. Additionally, the change in the energy ratio has insignificant effect on the weld width, and the deepest weld penetration depth is obtained when the laser energy ratio is 0.75. Moreover, the microstructure of the butt joint welded with the optimum energy ratio is mainly ferrite and bainite, and the elements are evenly distributed near the fusion line of the welded joint without element migration. The hardness peak near the heat-affected zone of the fusion line and that of the weld zone was considerably higher than that of the base metal. The hardness of the heat-affected zone decreased with the increasing distance from the weld center.