The invention discloses a method for load control of a steam turbine in a frequency-variable rotating speed reducing process of an SHRT (sinter blower residual heat recovery turbine) set. The method includes: step 1, starting the steam turbine, and detecting regulating steam port openness when the steam turbine is in a maximum non-load speed; step 2, performing rotating speed reducing control of the set, to be more specific, 1) when rotating speed reducing operation of the set is needed, setting VFDS frequency or rotating speed by operating personnel; sending a 'preparing for rotating speed reduction' signal to an instrument control system by VFDS, judging whether the set meets speed regulating conditions or not by the instrument control system, and if yes, feeding a 'permission of rotating speed reduction' signal to VFDS7, and executing the step 2); 2) reducing the rotating speed of a motor to a target rotating speed S1 under the control of VFDS, and in a rotating speed reducing process, reducing output power of the steam turbine to guarantee that current of the motor is constantly set current II. The method is free of human intervention, and the problem of frequency converter failure shutdown caused by current fluctuation of the motor in the rotating speed reducing process is effectively solved; in addition, enormous economic benefits can be created for enterprises by the SHRT set.