Accurately obtaining the micro-Doppler frequency generated by the rotating blade of wind turbine is a key step to solve the electromagnetic interference of wind farm to radar station. Aiming at the hypothesis defect of existing scattering-point integral algorithm, we introduced the concept of scattering center from the theory of high frequency electromagnetic scattering, and proposed an idea of solving the micro-Doppler frequency from the scattering centers of the blade. According to the generation mechanism of the micro-Doppler frequency of the blade, it was found that the key to solve the micro-Doppler frequency is to obtain the positional parameters of the scattering centers of the blade. For this reason, the positional parameters of the scattering centers of the blade were solved by the Estimated Signal Parameters via Rotational Invariance Technique method. Thus, an accurate solution of the blade micro-Doppler frequency was achieved. Finally, on the basis of the method, the effects of four influencing factors of blade rotation speed, incident electromagnetic wave frequency, azimuth angle and pitch angle on the micro-Doppler frequency of the blade were analyzed, which provides a theoretical reference for wind turbine clutter filtering on radar side.