A load control system was designed to keep the threshing load of the small-sized harvester in the rated load range, and the current detection for the motor driving the harvester cylinder was presented as a new method to detect the cylinder torque indirectly. First the mathematical relationship was established between the cylinder torque and the motor current, and the cylinder-load model was presented. Then the motor current according to the rated cylinder load was obtained by tests as the reference for the load control system. The results showed that the coefficient of variation of consistency of the motor current decreased from 10.7% by manual control to 7.4% by the load control system, and labor intensity index decreased to 8 from 13 after using the load control system. It indicates that the cylinder load control can improve the harvester performance and relieve manual labor required.