Abstract: The analysis of rotor aeroelastic and the prediction of vibration load are still challenges in conventional helicopter design. A rotor aeroelastic loads computing method was adopted and rotor dynamics issue in high speed forward flight was analyzed. With slender and flexible rotor blade, the rotor dynamics model was built with the Hamilton principle and the middle deformation beam theory. The aerodynamic model was built based on dual free wake model to catch the negative lift at blade tip and rotor interaction in high speed flight. Finally the computing method was validated and used in loads characteristic analysis. The result in B0105 rotor analysis indicated that the strong negative lift was rapidly grow at blade tip in advancing side, the lift offset moment was periodically alternate and pulsed. The harmonic loads of blade root vertical shear force and flap bending moment was rapidly grow, the fourth order harmonic amplitude of the root flapping moment increased the most. The fourth order harmonic of hub vertical force, roll moment and pitch moment was also rapidly grow, the increment of hub vertical force was the largest. The high frequency elastic torsion deformation appeared due to the strong negative lift and impulse moment, and the pitch link load was deteriorated.