Phosphorus (P) leaching in alkaline soils, exacerbated by excessive fertilizer application, represents a significant pathway for P loss. While soil pore structure and texture critically regulate P transport, mechanisms governing P loss in texturally diverse alkaline soils remain unclear. This study investigated P leaching dynamics and transport parameters across four alkaline soil textures (silty clay, clay loam, loam, sandy loam) using a one-dimensional convective-diffusion equation (CDE) based on column experiments. Results indicated that phosphorus leaching kinetics were predominantly governed by diffusion transport, evidenced by low Peclet numbers (P-e) (ranged from 0.02 to 0.31) across varying textures and initial P concentrations (C-0). Comparative analysis of transport parameters revealed significant textural effects on dispersion coefficient (D), retardation factor (R), pore water velocity (V), P-e, and diffusion coefficient (lambda) (F > 523.42, p < 0.001). Among these, only D, P-e and lambda exhibited substantial differences in response to variations in C-0 (F > 89.47, p < 0.001). Saturated hydraulic conductivity (K-s) (R-2 = 62.9%, p < 0.01) and total pore area (A) (R-2 = 12.4%, p < 0.01) emerged as primary regulators of P leaching. Enhanced clay content increased total pore area while reducing average pore diameter, concurrently decreasing pore water velocity and saturated infiltration rates. These textural modifications amplified diffusive P transport within soil matrices. The findings provide mechanistic insights into texture-dependent P mobility in alkaline environments, informing targeted strategies for agricultural phosphorus management.