The rotor blade double-swept-tip geometry can not only improve the aerodynamic performance ,but also effectively reduce the rotor noise. However,due to the particularity of the geometric structure of the double swept blade,the changes of the sweep-forward angle and the backward sweep angle have a great impact on its dynamic characteristics,so it is necessary to study the dynamic characteristics of the double swept blade. The motion equation of the balde was derived with the Hamilton theory,the rotor system was simplified with the finite element method,the natural frequency of the blade were obtained by solving the generalized eigenvalue.In this basis,the influence of sweep-forward angle and sweep-backward angle on blade dynamic characteristics were analyzed,the results showed that sweep-forward angle and sweep-backward angle have little influence on the low natural frequencies of the balde,and the fourth and fifth natural frequencies of the blade gradually decrease with the increase of sweep-backward angle.The research results provide technical support for the optimization design of double-swept blades.