Based on conventional wind turbine point-scattering model,an infinite well-conductive ground model taking angle into account was established.Then,according to the multipath effect,four radar electromagnetic wave propagation paths amony radar,wind turbine and ground were specified and the solving formulas of the radar echoes of wind turbine in the presence of ground were derived by using image theory.The mathematical method of short-time Fourier transform(STFT)was used to get the time-frequency diagram of echoes.The results show that the scattering effect of ground on radar electromagnetic wave results in more complex composition of echoes,which leads to an increase in the number of Doppler flashings,and the tilt of ground results in the change of the maximum Doppler frequency of echoes.Therefore,it is recommended that the influence of ground must be considered in the study of the echoes of wind turbine.