The invention provides a speed adjusting controller for an industrial steam turbine. The speed adjusting controller comprises an oil pump (1) and a pressure accumulation chamber (3). The speed adjusting controller is characterized in that the oil pump (1) and the pressure accumulation chamber (3) are connected with a piston cylinder (6) through a high-pressure pipeline (4), a power piston (7) is arranged in the piston cylinder (6), the upper end of the power piston (7) is connected with one end of a chain link (8), the other end of the chain link (8) is hinged to an output lever (9), a feedback lever (12) is installed on an output shaft (11), the upper end of a control lever (14) is connected with the output end of a speed matching motor (15), the feedback lever (12) is connected with the speed matching mechanism, and an internal gear oil pump (20) is installed at the lower end of the speed matching mechanism. The speed adjusting controller is compact in structure, motion is sensitive and reliable, fine adjustment of the closing length of a control sliding valve is achieved through the speed matching mechanism according to the lever principle, the reliable performance of speed adjusting control is greatly improved, and the speed adjusting controller can be widely applied to adjustment control over the rotating speed of the industrial steam turbine.