Helicopter has the unique advantages of taking off and landing, hovering and low altitude maneuvering flight, and plays an important role in the field of military and civil aviation. However, low speed, high fuel consumption, short range and high noise have become important limitations to further expand the application market in both military and civil fields. Variable rotor speed technology can dynamically adjust the rotor speed according to the changes of flight conditions, so as to overcome the above shortcomings to a great extent and improve the comprehensive performance of helicopters. Therefore, it has become an important research topic in the field of helicopters. At present, variable rotor speed technology still faces many challenges in terms of the impact on helicopter performance, the optimization and control of variable rotor speed, the control in the process of variable rotor speed and the implementation of variable rotor speed. Based on this, this paper summarizes the research results of variable rotor speed technology at home and abroad, and focuses on the current situation of variable rotor speed technology from three aspects: the impact analysis of variable rotor speed on helicopter performance, the optimization and control of variable rotor speed, and the realization of variable rotor speed technology, aiming to provide a valuable reference for the development of variable rotor speed technology of high-performance helicopter.