The invention relates to a pulse compression technology based broadband measurement method for sound velocity and attenuation in a sediment. During sound velocity measurement, firstly the receipt signal when the sound wave only penetrates a glass jar without the presence of a sand sample is recorded, then a sound source and a hydrophone are moved to a thick sand sample side to record a corresponding receipt signal. During attenuation coefficient measurement, the receipt signals penetrating two sand samples of different thicknesses are recorded successively. In the measurement, the receipt signal under each state is collected for at least 30 times, statistic analysis on the measurement results of sound velocity and attenuation coefficient are carried out, and the confidence interval determined by the result of a mean value+/-standard deviation is taken as the final measurement result. The method provided by the invention can acquire the variation relationship of the sound velocity dispersion and attenuation along with the frequency in the sediment within the measurement band at a time, and provides a new idea for realizing rapid acquisition of the sound velocity and attenuation.