The invention discloses a novel hydroelectric generating set load and frequency controller. On the basis of a conventional controller, the guide vane opening degree feedback is changed into load feedback of a hydroelectric generating set, and a variable parameter speed limiting module is disposed at an outlet of a controller. The controller solves problems of additional risks caused by load feedback and possible water attack caused by a set control system through speed limiting, and controls the water attack through limiting the maximum closing speed. On the basis of a classic hydroelectric generating set PID controller, the interior of the controller is additionally provided with a water attack force control link from the aspects of water attack and frequency modulation, thereby effectively limiting the amplitude of a water attack force from a source, avoiding the excessive limit of an execution mechanism movement speed, and improving the frequency modulation capability of the set under the condition of protecting the safety of equipment. Moreover, the controller plays an important role in improving the primary frequency modulation quality of the hydroelectric generating set and the frequency stability of a power grid.