The utility model provides a steam turbine speed regulation device which comprises a speed regulator, a synchronizer, a servomotor and a steam distribution mechanism, wherein the synchronizer and the servomotor are connected with the speed regulator, and the steam distribution mechanism is connected with the servomotor; the speed regulator is used for converting a rotation speed signal of a rotor into a primary control signal; the servomotor is a hydraulic position servo motor and used for generating driving force used for driving the steam distribution mechanism to act according to a control signal of an intermediate amplifier to drive the steam distribution mechanism to a preset position; the steam distribution mechanism is used for converting the stroke of the servomotor into the opening of various regulating steam valves, and the steam inlet quantity of the steam turbine and the stroke of the servomotor are corrected to an approximate linear relation through the nonlinear transmission characteristics of the steam distribution mechanism; and the synchronizer is used for acting on the intermediate amplifier to generate a control signal for controlling the stroke of the servomotor, changing the rotation speed of the steam turbine during stand-alone operation and changing the power of the unit during grid-connected operation. The steam turbine speed regulation device has the advantages of small inertia and high drive power.