With the large-scale installation of horizontal axis tidal turbines (HATTs), the hydroelastic problem of blades is gradually becoming apparent. Therefore, this paper applies the Fluent and Transient Structural modules in ANSYS software to establish a transient analysis of the HATT based on bidirectional fluid structure interaction method, and obtains the hydrodynamic (power and axial load coefficients) and structural (deformation and stress of the blades) characteristics of the HATT under wave-current conditions. The results show that: under the wave-current condition, the power and axial load coefficients of the HATT, as well as the deformation and stress of the blades, exhibit periodic fluctuations with wave motion, and the fluctuation amplitude increase with the increase of the wave period and wave height. Therefore, it is not conducive to the safe operation of the HATT under the large wave. On this basis, the hydrodynamic load of the HATT is decomposed using the least squares method, and it is found that the deformation of the blade structure changes the mean value of power and axial load coefficients. The stress concentration occurs at the leaf root connection, so the blade design should pay more attention to the structural strength at the leaf root. The research results of this paper can provide an effective method for predicting the load of the HATT, and provide reference basis for the structural design of the HATT.