Measurements of echolocation signals of three finless black porpoises bred in a stream near the seashore show that finless black porpoises can emit not only high frequency pulse but also low frequency pulse. During the course of experiment, five different kinds of low frequency pulse and four different kinds of high frequency pulse were recorded. Oscillogram and spectrum were presented after these sound signals were analysed in laboratory. It was also found that the high frequency signals had a maximum energy between 60 and 70kHz which is much higher than echolocation signal of N. phocaenoides reported by Purves et al., yet the peak energies of low frequency pulses are different from each other. The time intervals between two successive pulses in a pulse train were found to be highly variable, the pulses of intervals from 4 μs to 9 μs account for about 62.4%. The sound presure levels of the echolocation signals in reference to 1 m distance in front of the animals’ rostrums were in general between 104dB and 107dB re. 1 μPa(0dB=1 μPa )and closely associated with animals' speed. The faster the speed, the higher the sound presure levels.