Global climate change has significantly changed the spatiotemporal distribution of precipitation and air temperature. Due to the particular physical geographical conditions, drought events in China occurred frequently with a trend of increasing during the past decades. Especially, extreme drought events, that seriously affected agricultural production and food security, have resulted in huge losses in agriculture. In this proposal, a distributed hydrological model including an improved crop growth module will be developed. The crop yield will be estimated at watershed scale, and the spatial-temporal evolution pattern of agricultural drought will be analyzed. The disaster mechanism of agricultural drought will be investigated, and the loss of agricultural drought will be evaluated in the Wei River basin. Firstly, the hydrological cycle of the Wei River basin will be simulated by the distributed hydrological model, and the crop growth module of the model will be modified; Secondly, the proposed drought index based on the concept of blue and green water, combined with existing drought indices will be used to analyze the agricultural droughts in the Wei River basin; Finally, the mechanism of agricultural drought hazard in the Wei River basin will be investigated, and the responses of crop yield to water deficit will be quantitatively analyzed. The crop water production function will be established, and the impact of drought on crop yield will be evaluated. This study will provide theoretical basis and technological support to mitigate the impact of droughts on agriculture.