Production method for thick-specification high-strength steel plate material

The invention discloses a production method for a thick-specification high-strength steel plate material. The production method comprises the working procedures of converter smelting, LF refining, RHrefining, continuous casting, heating, rough rolling descaling, rough rolling, finish rolling descaling, finish rolling, cooling and slow cooling, wherein the RH refining vacuum degree is less than orequal to 120 KPa, and the maintaining time is larger than or equal to 8 min; heavy press down and electromagnetic stirring are adopted in the continuous casting, the press down quantity of the heavypress down is 15-30 mm, and the electromagnetic stirring electric current is larger than or equal to 440 A; the rough-rolling single pass press down rate is 15-25%, the total press down rate is 50-70%, and the initial rolling temperature is 1000-1200 DEG C; and the finish-rolling initial rolling temperature is 850-930 DEG C, the finish rolling temperature is 750-850 DEG C, the finish-rolling single pass press down rate is 8