When the rotor is in operation, it is subjected to intense changes in aerodynamic loads. The action of these aerodynamic loads causes structural deformation, which in turn reacts on the flow field distribution, forming a complex two-way coupling process. For the aeroelastic coupling calculation and analysis of rotor blades, a calculation model based on bidirectional FSI (fluid-structure interaction) analysis was proposed. Firstly, in terms of fluid calculation, the nested sliding mesh was adopted, combined with RANS (Reynolds-averaged Navier-Stokes) equations, to ensure both calculation accuracy and efficiency. Secondly, in terms of dynamics, the finite element method was used to discretize the rotor blades, forming the structural model of the rotor blades. By comparing the aerodynamic calculation results under the loose and tight coupling modes with the measured data, the differences between different coupling modes were analyzed. Taking tight coupling as an example, the one-way and two-way coupling methods were used to calculate the structural response of the rotor blades. Finally, the tight coupling mode was used to perform bidirectional FSI calculation on the rotor with trailing edge flaps. The results show that the high data transfer frequency of tight coupling can timely capture and update the differences in the rotor flow field caused by the deformation of rotor blades in the calculation of the rotor with trailing edge flaps, it is found that as the deflection amplitude of the flaps increases, the stress at the blade root increases.