The invention discloses an industrial steam-extraction method with adjustable medium pressure for a large-power steam turbine. The industrial steam-extraction method disclosed by the invention has the beneficial effects that according to the heat-power load distribution condition of the rated industrial steam-extraction working condition in design requirements, under the premise of constant total area of medium-pressure adjusting valves, the quantity of the medium-pressure adjusting valves is increased, and the sizes of throat parts of all the valves are reasonably designed according to the amount of industrial steam extraction so as to lead parameter-adjusting valves under the rated heat-supply working condition to operate at valve points; in addition, when the heat-power load is changed, the adjusting strokes of multiple valve groups are larger, and the quality is better, so that the valve-position fluctuation of the medium-pressure adjusting valve when in heat supply with largest steam-extraction working condition or lower power load is effectively avoided, the technical requirements of industrial heat supply for stability and reliability of high-quality steam are guaranteed; and the system design is simple, the engineering investment risk is less and the operation economy is better.