Due to the influence of the electromagnetic field and environment, there are spikes in the measured digital signal of carrier machinery. Eliminating the spike accurately is a key work of the digital signal processing. The algorithm based on the racetrack method of eliminating spike was put forward. This algorithm detects the spike according to the changing trends of the data, distinguishes spike and normal data obviously. Compared with the treatment results with amplitude threshold detection and differential threshold detection, the results show that the algorithm based on the racetrack method of eliminating spike is better than the others.