The invention discloses a multi-sensor technology-based grape water stress diagnosis method and a system therefor. The multi-sensor technology-based grape water stress diagnosis method comprises the following steps of 1, acquiring a canopy coverage rate value, a canopy temperature characteristic value and a canopy photosynthetically active radiation value of a grape sample for modeling, 2, building a detection model by the canopy coverage rate value, the canopy temperature characteristic value and the canopy photosynthetically active radiation value as input variables, and a canopy water stress level as an output variable, and 3, by the step 1, acquiring a canopy coverage rate value, a canopy temperature characteristic value and a canopy photosynthetically active radiation value of a grape sample needing to be detected, and substituting the acquired canopy coverage rate value, the canopy temperature characteristic value and the canopy photosynthetically active radiation value into the detection model, and calculating a canopy water stress level of the detected grape sample. Through utilization of the multispectral imaging technology, the thermal infrared imaging technology and the multiple informative data fusion technology, the multi-sensor technology-based grape water stress diagnosis method realizes fast, early-stage and real-time detection of a grape water stress level and improves a detection precision.