In the velocity measurement of the spinning flying target, the receiving signal would be modulated by the microDoppler caused by the spinning of target, which would effects the measurement of motion parameter. The microDoppler with a property of time varying would different effects on the measurement of motion parameter under different conditions. In this paper the microDoppler model of cooperative spinning target is deduced with the operating mode of transponder. And the theoretical model of receiving signal is derived based on the microDoppler model. Then we have verified the microDoppler modulation and the effect of the frequency spectrum, and validated the correctness of the model through the simulation. At last the measurement interval applied to the measurement of different motion parameter is concluded by the analysis of the simulation.