Research on the cross-domain flow pattern of agricultural virtual water can reveal the deeper relationship between trade and regional water shortage, which is of great significance for ensuring food security, optimizing water resources allocation, and promoting high-quality regional development. As the largest urban agglomerations in China, the Yangtze River Delta has frequent internal resource flows and close agricultural trade with other domestic regions. But it also faces risks such as water shortage. Taking the Yangtze River Delta as an example, this paper constructs the input-output model of water resources expansion to calculate the agricultural virtual water flow momentum, and combined with the virtual water balance state and water resources pressure state, the influence of the virtual water flow relationship driven by agricultural products trade in domestic urban agglomeration is explored. The results show that: from the state of regional water resources, the pressure state of water resources in the Yangtze River Delta is relatively high, and the water use contradiction is prominent. The state of virtual water balance is highly dependent on the inflow of virtual water from outside the region. From the perspective of time, since the new normal of economy, the Yangtze River Delta has always shown a state of net agricultural virtual water input, with the input of virtual water resources on the whole showing an upward trend, while the self-sufficiency rate of virtual water shows a downward trend and then an upward trend. Before and after the structural reform of agricultural supply side, the flow structure of agricultural virtual water in the Yangtze River Delta has changed, and Jiangsu Province has replaced Anhui Province as the most important source of virtual water in Shanghai. From the spatial dimension, the virtual water flow in the Yangtze River Delta presents a chain structure of "Anhui-Jiangsu-Zhejiang-Shanghai". The Yangtze River Delta and the rest of the country show a virtual water flow feature of "one-way flow in the north and two-way interaction in the south". Finally, based on the perspective of virtual water strategy implementation, relevant policy suggestions are put forward from the perspectives of guiding the orderly flow of resource elements within the region, perfecting the value realization mechanism of ecological products and improving the inter-regional trade structure, so as to provide references for adjusting and optimizing the regional agricultural production and trade pattern and promoting the construction of urban agglomeration in harmony between people and water. [ABSTRACT FROM AUTHOR]