The invention discloses a method for producing a super-thick steel plate. The method comprises the following production process steps of: performing pretreatment on molten iron; making steel by using a convertor; performing external refining; continuously casting; heating; rolling; cooling in an accelerated way; normalizing; controlling a cold condition; finishing; inspecting performance; and performing ultrasonic flaw detection. In the method, a low-C high-Mn component system is utilized, and Ni and Cu alloy elements are added into the steel in combination with micro-alloying treatment of Nb, V and Ti. The steel comprises the following chemical components in percentage by weight: less than or equal to 0.12 percent of C, 0.20 to 0.40 percent of Si, 1.20 to 1.50 percent of Mn, less than orequal to 0.008 percent of P, less than or equal to 0.003 percent of S, 0.03 to 0.06 percent of AlT, less than or equal to 0.10 percent of Nb, Ti and V, less than or equal to 0.80 percent of Cu and Ni, less than or equal to 0.40 percent of Ceq and the balance of Fe and inevitable impurities. By the method, a continuous casting blank is used for producing high-performance Q345R steel plates with the thickness of 60 to 100mm, so that production cost is reduced, and the requirement of manufacturing containers with high parameter pressure is met; the low-C high-Mn component system is used for a component design, so that the requirement that the material Ceq is less than or equal to 0.40 percent is met; and the continuous casting blank is used for producing a high-performance Q345R super-thick plate, so that the method has a simple process, the process is easy to realize, and the plate can be produced by a common wide and thick plate factory.