According to the common phenomenon of beating vibration in helicopter coupled systems caused by the rotation of the main rotor, tail rotor, and operating engine, which might lead to structural fatigue, electronic equipment failure, and passenger discomfort, a three-degree-of-freedom concentrated mass model considering the impact of beating vibration is established. Selecting representative vibration parameters based on existing literature experimental platform, vibration responses are analyzed from time-domain, phase diagrams and frequency-domain characteristics. It was explained that as the difference in beat frequency increases, the amplitude value and extreme difference of beating decrease, and at the same time, the response and amplitude of the beating vibration are significantly higher in the hovering state than in the forward flight state. Dynamically adjusting the damping coefficient could weaken the beating vibration response. This provides a good theoretical basis for the vibration reduction structure and frequency design of the main rotor, and tail rotor.