Abstract: Prawns will make noises passively when they eat. Investigating the effects of different particle sizes of pellet feed on the characteristics of feeding sound signals of L. vannamei can provide a theoretical basis for the application of automatic feeding based on feeding sound signals. With passive acoustic method, we recorded the acoustic signals of L. vannamei (Body length of 9−10 cm) feeding pellets of different sizes (0.4, 0.8 and 1.2 mm) in the laboratory. The results of the waveform, spectrogram and spectrum map reveal that the characteristics of feeding acoustic signals by feeding pellets of different sizes were similar, and the frequencies were 5−45 kHz. The spectral frequency peak of acoustic signals of the shrimps fed with pellets of 0.4 and 0.8 mm was about 17 kHz, and that of shrimps fed with pellets of 1.2 mm was about 10 kHz. In addition, there were obvious differences in the acoustic signals between feeding Nereis succinea and pellets. The frequency range of acoustic signals of feeding N. succinea was 5−45 kHz, and the spectral frequency peak was about 7 kHz. Finally, compared with the feeding acoustic signals of L. vannamei in farming pond, it is found that the signal characteristics collected in the pond were similar with those in the laboratory, and the only difference is that there was no secondary peak in the high frequency region of signals in the pond-cultured shrimp.