The invention discloses a 485MPa level TMCP+ tempering weather-proof bridge steel plate and a production method. The steel plate is formed by smelting following chemical components including, by weight percent, 0.05%-0.08% of C, 0.25%-0.50% of Si, 1.20%-1.40% of Mn, smaller than or equal to 0.012% of P, smaller than or equal to 0.005% of S, 0.25%-0.40% of Ni, 0.45%-0.7% of Cr, 0.25%-0.4% of Cu, 0.02%-0.08% of Mo, 0.015%-0.030% of Nb, 0.020-%-0.050% of Al, 0.040%-0.070% of V, and the balance Fe and inevitable impurities. According to the steel plate production method, molten steel is subjected to the procedures of smelting, continuous casting, heating, rolling, cooling and tempering, and then the steel plate is obtained. The large-thickness yield 485MPa level TMCP+ tempering weather-proof bridge steel plate produced through the method has the beneficial effects that the low equivalent carbon equivalent and crack sensitive indexes and the low yield ratio are achieved, the low-temperature impact strength is excellent, and the welding performance is good.