Abstract: Alluvial fan area is the main area of agricultural development, and also the sensitive area of nitrogen leaching. At present, the understanding of the spatial and temporal distribution of soil water and nitrogen leaching fluxes in deep soil at the scale of alluvial fan area is still limited. In this study, the farmland in the north of the alluvial fan of Hutuo River was selected as the main research area. Based on the improved HYDRUS parallel calculation and simulation method, the soil water and nitrate nitrogen transport processes were simulated during 1975-2021. The results show that: Water and nitrogen fluxes and soil nitrogen accumulation were determined by different crop types in the study area. The average annual water fluxes of different crop types were vegetable area (351mm) > wheat and corn field (98mm) > orchard (87mm) > cotton (54mm). The annual average nitrogen loss was in vegetable area (374kg/ha) > wheat and corn field (68kg/ha) > orchard (23kg/ha) > cotton (21kg/ha). The average annual nitrogen accumulation rate was 2432kg/ha in vegetable area > 1508kg/ha in wheat and corn area > 1504kg/ha in cotton area > 364kg/ha in orchard. Crop type not only affects the spatial distribution of soil water and nitrogen flux, but also determines the lag time of response of nitrate leaching to surface nitrogen input. The lag time of nitrogen leaching in vegetable area was the shortest due to high irrigation and fertilization, followed by wheat/corn area, and the longest in cotton area and fruit area. The relationship between water recharge flux and nitrogen accumulation, nitrogen leaching loss and denitrification amount was different in different land use types. Nitrogen accumulation, nitrogen leaching loss and denitrification amount were positively correlated with water recharge flux in vegetable area and wheat/corn area, while there was no significant correlation between fruit area and cotton area. The research can provide scientific support for regional non-point source pollution prevention and control and groundwater quality protection.