The automatic and real time irrigation system based on detecting of water shortage information in crops with acoustic emission (AE) technology was studied and developed, an experimental study in greenhouse with the crop of tomato as the target was carried out. PCI-2 AE board-card, R 15 sensor, electronic balance, temperature sensor, humidity sensor, CO2 sensor, illumination sensor and PCI-8333 DAQ were adopted to compose the hardware detecting system, the virtual instrument technology was used to construct the software system, the three factors of soil, crops and atmosphere in SPAC system were effectively integrated, the real time acquisition and detecting system of information between crop acoustic emission and each environmental factor was established. It shows that: to some extent, the frequency counts of AE of the crops in water stress increase gradually with the increase of the water stress extent in crops, and are related with the transpiration rate of crops, in order to avoid the influence from water stress on crops, it has the potential to realize the automatic irrigation and regulation in crops based on the information acquired from crops with AE sensor, to make the transpiration amount and irrigation amount of crops achieve an balanced regulation, aiming to make the crops grow in an optimum soil water environment, to increase the utilization of water, and improve the quality of crop fruit.
