The invention discloses a 460MPa-grade high-toughness low-alloy high-strength structural super-thick steel plate. The chemical ingredients of the steel plate comprise 0.03-0.09% of C, 0.10-0.40% of Si, 1.20-1.60% of Mn, 0.01-0.05% of Nb, 0.005-0.030% of Ti, 0.01-0.04% of V, 0.015-0.045% of Als, 0.015% or smaller of P and 0.008% or smaller of S, and further comprise one or two kinds of 0.01-0.30% of Cr, 0.01-0.08% of Mo and 0.05-0.25% of Ni, and the balance Fe. A production method comprises the steps of smelting, refining, continuous casting, steel billet heating, controlled rolling, controlled cooling, slow cooling and obtaining of the finished product. The super-thick steel plate is good in performance, the impact energy KV2 at -60 DEG C of the 100 mm thick plate is larger than or equal to 200 J, the carbon equivalent is not larger than 0.38, the yield ratio is smaller than or equal to 0.85, the cost is low, the production process is simple, and operation is easy.