Abstract: A 3-year stationary field experiment of N application rate was carried out to explore soil inorganic nitrogen desorption characteristics and simulation model, and the effect of the desorption characteristic value and vegetable-rice rotation on nitrate nitrogen concentration in percolating water in field under the garden bean-zucchini-paddy rice rotation system. The results showed that desorption process met well the desorption model ofC =C 1H -a (0＜a ＜1) because of the relatively simple form of soil inorganic nitrogen, and it was feasible to simultaneously acquire inorganic nitrogen desorption characteristics that reflected biological effectiveness of soil nitrogen, soil inorganic nitrogen concentration and its buffer coefficient. The vegetable-vegetable-rice rotation system could reduce soil nitrate nitrogen concentration significantly, which was 41.3% of vegetablevegetable rotation. According to the modeling method of“dual rate turning point”, the average turning point of soil inorganic nitrogen desorption amount was 250.4 mg/kg and varied very slightly both in vegetablevegetable- rice rotation and vegetable-vegetable rotation. Therefore, vegetable-vegetable-rice rotation system is conducive to reduce nitrate nitrogen concentration in percolating water, and the dual rate turning point of soil inorganic nitrogen desorption amount could be used as one of the indices to evaluate the potential of soil inorganic nitrogen leaching loss in vegetable field.