Abstract: In this paper canopy temperature was measured with an infrared thermometer, air temperature, dry and wet-bulb temperature, and soil water content were measured as well to establish the model for determining the CWSI(crop water stress index) of flowering Chinese cabbage. The relationship between canopy-air temperature difference and vapor pressure deficit was determined. The preliminary model was established with regard to the influence of radiation intensity. A microcomputerized real-time data acquisition system was developed to monitor water-stress status for scheduling irrigation of vegetables.