The invention provides a steel plate for a low-carbon high-niobium high strength welding structure. The steel plate comprises the following chemical components in percentage by weight: 0.015 to 0.075 percent of C, 0.20 to 0.50 percent of Si, 1.62 to 2.0 percent of Mn, 0.081 to 0.120 percent of Nb, 0.005 to 0.030 percent of Ti, 0.0005 to 0.0030 percent of B, 0.25 to 0.70 percent of Cr, 0.27 to 0.70 percent of Cu, 0.15 to 0.50 percent of Ni, 0.010 to 0.050 percent of Als, and the balance of Fe and inevitable impurities. The method for manufacturing the steel plate comprises the steps of molten iron pretreatment, rotary furnace smelting, refining, continuous casting and rolling, wherein the rolling process adopts the HTP plus RPC process, the heating temperature before rolling is between 1,140 and 1,220 DEG C, and two-stage controlled rolling is adopted. The steel plate is low in C content and high in Nb content, and Mo is not added, so that by the HTP plus RPC process, the steel property of the steel plate is improved, and the yield strength of the steel plate is over 690MPa; and compare with other low-Nb steel plates at the same strength level, the steel plate of the invention can realize the non-recrystallization rolling at a higher temperature, thereby shortening the temperature holding time, reducing the load of a rolling mill and enhancing the manufacturing efficiency.