Abstract: According to the echo range migration of the high speed moving target in the tracking phase,the characteristic of the echo is analyzed,then a novel method of compensating the envelop migration,based on transmit signal preprocess,is proposed.Based on the high Doppler tolerance of the echo,the method makes envelops of echo pulses neat automatically in the fastslow time domain by stretching the transmit signals.At the receiver,combining the Dechirping method, two index phases caused by the acceleration can be compensated, echo’s Doppler shifting be compensated simultaneously.This method requires tiny calculating quantities and is easy to achieve.The results of simulation proved the validity of the method presented.