There are complex structural load changes in the rotor during the tilt-transition of quad-tiltrotor aircraft, which directly affects the life of the rotor. The control strategy analysis is beneficial to reveal the influence law of the rotor structural load, providing a conclusion basis for the future research on vibration suppression. In order to study the influence of tilt-transition control strategy on rotor dynamic characteristics, a comprehensive flight dynamics model of tiltrotor is established, two typical control strategies of tiltrotor transition state are designed, and the trim characteristics and aerodynamic load characteristics of the fixed tilt angle state are studied through numerical simulation, as well as the influence of the transition state control strategy on the dynamic characteristics of the rotor. First of all，this paper establishes a flight dynamics model for a quad-tiltrotor in full-mode flight, introduces the weight coefficient of the control input, integrates redundant control variables into each control channel, and obtains the control strategy for the transition state of the quad-tiltrotor. It then uses numerical simulation methods to study the trimming characteristics and calculates the aerodynamic loads on the rotor blades in the trimmed state. By considering the influence of aerodynamics on structure, the aerodynamic loads are treated as external forces applied to the blade surface, and the blade dynamics equation is solved using finite element method. The displacement response is obtained by solving the equation, further obtaining the dynamic characteristics of the tilt-rotor quadcopter in transition flight, thus conducting an analysis of the influence of transition state control strategy on the rotor dynamic characteristics. The results show that periodic variable-pitch control during transition flight can reduce the aerodynamic loads on the rotor, thereby reducing the rotor vibration response and achieving load reduction on the rotor structure.