In order to reveal the migration and transformation of different forms of nitrogen in the wetted soil under the influence of fertilizer solution (urea) concentration, clay loam and sandy loam were selected as the different soil textures for infiltration experiments, and we quantitatively analyzed the influences of fertilizer concentration on soil cumulative infiltration and transport and transformation characteristics of different forms of nitrogen in the process of distribution and redistribution. The results showed that during the same infiltration time, the cumulative infiltration increased with the increasing of fertilizer concentration, and a linear relationship between the infiltration coefficient of Kostiakov equation and fertilizer concentration were found. The estimation equation of cumulative infiltration considering the effect of fertilizer concentration was established and verified. The simulated value was in good agreement with the measured value, and the average absolute value of relative error between them was less than 8.0%. At the end of infiltration, the contents of urea nitrogen, ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) at the same position all increased with the increasing of fertilizer concentration. NH₄⁺-N mainly distributed above 20 cm of soil wetted depth, and the contents of urea nitrogen and NO₃^--N decreased with the increasing of soil wetted depth.During the redistribution process, the contents of urea nitrogen in clay loam and sandy loam decreased with the increasing of redistribution time, and the hydrolysis of urea nitrogen in the wetted clay loam and sandy loam was basically completed at the 5^th and the 3^rd days of redistribution, respectively. The content of NH₄⁺-N increased first and then decreased, the peak value of NH₄⁺-N content clay loam appeared within the range of the 3~5 days in redistribution, while that of sandy loam appeared about around 3 days in redistribution. The content of NO₃^--N in clay loam increased first and then decreased, and its peak value appeared within the range of the 5~10 days in redistribution, while the content of NO₃^--N in sandy loam remained at a high level after 10 days. The research results could provide theoretical basis and technical support for the design and management of irrigation and fertilization system.