In order to acquire the characteristics of acoustic emissions signal of tomato at different growth stages，this paper measured under 6 000 Pa value the water consumption，soil moisture content and acoustic emissions signal of tomato plant，etc. indexes with negative pressure irrigation in tomato potted cultivature
experiment；and studied the changes in water consumption，soil moisture content，acoustic emissions signal and spectral characteristics parameter of tomato plant at different growth stages under negative pressure irrigation. The results showed that the water consumption of tomato plant in initial fruit and full fruit stages was significantly higher than that in seedling stage and flowering stage，and the changes of soil water content tended to be stable after gradually decreasing. The results of continuous monitoring of AE signal indicated that the acoustic emission signal of tomato flowering to fruiting stages，AE signal waveform parameters were decreased gradually，the resonance peak frequency showed a gradual upward trend. The results of Pearson correlation analysis showed that the environmental temperature of greenhouse and soil content was positively correlated with the amplitude of AE waveform parameters，respectively. In summary，through comparative analysis of the characteristics of AE signals，waveform parameters and spectral characteristics of tomato in different growth stages，the ultrasonic signal number，frequency and energy could be associated with tomato growth stages.