To investigate the effects of urbanization intensity on soil particle size composition and fractal characteristics in Nanchang, soils in the built-up areas of Nanchang were sampled according to the impervious surface area as a percentage of the urbanization intensity level (184 plots), soil particle size composition, physicochemical properties and vegetation indexes were determined, and fractal dimension values were calculated by soil particle volume fractal dimension model. The results showed that urban soil particles were dominated by silt particles (46%-59%) and sand particles (40%-53%), and high urbanization increased sand particles but decreased silt particles. The fractal dimension varied from 2.69 to 2.97, which showed a decreasing trend with increasing urbanization intensity. Silt particles were positively correlated with fractal dimension while sand particles were opposite, and silt particles showed the greatest influence on fractal dimension. Pearson correlation analysis and Structural Equation Model analysis showed that abundant vegetation reduced the loss of soil particles, improved soil physical properties, and mitigated soil degradation. In conclusion, soil particles of medium size, such as silts and very fine sands, in urban green spaces can preferably retain water and nutrients and reflect soil quality.