The invention relates to a production method of a formable high-strength medium-thickness steel plate, which comprises the following steps: converter steelmaking, ladle furnace refinement, vacuum treatment, continuous casting, heating, rolling, pre-straightening, on-line quenching, and tempering heat treatment. The steel comprises the following components in percentage by mass: 0.07-0.09% of C, 0.15-0.30% of Si, 1.60-1.80% of Mn, at most 0.015% of P, at most 0.005% of S, at most 0.10% of Nb+V+Ti, at most 0.50% of Cr+Mo, at least 0.020% of Alt and at most 0.23% of Pcm. The Q800E steel plate produced by the method is still in good condition when being subjected to 200mm-wide cold bending; the cold bending property of the real steel plate satisfies the requirement of the consumer for formability; the yield ratio of the steel plate is less than 0.92, and the uniform elongation is greater than 8%, thereby satisfying the operational requirements of related design; the product of strength and elongation is enhanced by more than 35%, the dynamic loading resistance of the high-strength steel plate is enhanced, and the safety of equipment is improved; the hot charging and on-line quenching of the continuous casting billet lower the production cost; and the composition design of less than 0.23% of Pcm enhances the weldability of the high-strength steel plate.