Abstract: In order to detect the carrier velocity, a detection algorithm was presented taking the advantage of the high sensitivity and high responsively of the GMI effect magnetic sensor. Two GMI sensors were placed on the carrier at a certain distance to detect magnetic target. According to the detected value of the magnetic variation, the corresponding curvilinear time difference could be gotten with the indirect cross-correlation algorithm, so the carrier velocity could be obtained. Experiment result show that the velocity error can be controlled within 10% with the method, and it meets the real-time requirements under the carrier velocity about several decameters per second.