To solve the problem of large Doppler frequency offset generated by user equipment (UE) in the ultra high speed mobile communication systems, this paper proposes a new detection algorithm based on a new restricted set method to generate random access preamble sequences. According to the characteristics of power dispersion caused by the new frequency offset, the proposed method uses five detection windows to jointly detect the random access preamble sequences. First, the maximum peak power of each window in the five candidate windows is found and recorded. Then, the peak power of the five candidate detection windows is superposed as the preamble to detect the peak power. The simulation results show that the method can effectively affect the detection of random access preamble with large Doppler shift.