In order to improve the detection probability of range-spread targets in white Gaussian noise, a detector using waveform contrast is proposed based on multiple-pulse trains. Firstly, sliding cross correlation is utilized to eliminate the detrimental influence of range migration. Then, arithmetic mean algorithm is adopted to synthesize the final high-resolution range profiles (HRRPs). Finally, the waveform contrast factor based on multiple pulses is employed to form the detection statistic. The experiments confirm the effectiveness and advantages of the proposed detector compared with the conventional range-spread target detectors.