A rotor aeroelastic loads computing method was adopted and rotor dynamics issue in high speed forward flight was analyzed, aimed at the problem of rotor dynamic load variation caused by different tip twist distribution design of conventional helicopter. With slender and flexible rotor blade, the rotor multi-body 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. The computing method was validated and used in loads characteristic analysis with the influence of blade tip twist design. Taking the BO105 rotor as the research object, analyzed the aerodynamic and structural load effects of several blade tip twist distributions on the rotor. The results indicate that increasing the linear negative twist of the blade is beneficial for improving the overall aerodynamic efficiency of the rotor at low speeds, with minimal impact on the rotor's dynamic load. But as the forward flight speed increases, the blade tip generates negative lift and the rotor dynamic load increases. Both the forward twist design of the blade tip and the swept back layout design are beneficial for reducing the dynamic load level of the rotor, and the wind tunnel test results of the 4 m model rotor also verify that the vertical force dynamic load level of the hub using the forward twist design of the blade tip is lower.