［Objective］ Preferential flow development and its effects on solute transport under different rainfall conditions in typical farmland in Hainan were examined to provide a theoretical basis for agricultural water pollution control and risk prevention in tropical areas. ［Methods］ Using typical latosol in Hainan Province as the research subject， field dye tracing， Br^- simulated solute transport， and image analysis techniques were used to investigate the development of preferential flow and ion distribution in soil vertical profiles under different rainfall conditions. Correlations between preferential flow indices， composition ratios of interflow types， and ion concentrations in preferential flow zones and soil matrix zones were analyzed. ［Results］ ① Under heavy rain （30 mm） and rainstorm （60 mm） conditions， the total stained areas were 506.85 cm² and 857.86 cm²， respectively. The maximum staining depths were 16.80 cm and 31.08 cm， respectively. The evaluation indices for preferential flow were 0.25 and 0.55， respectively， indicating that the degree of preferential flow development was higher when rainfall increased from 30 mm to 60 mm. ② With 30 mm rainfall， the ion concentrations in the preferential flow paths of the 5—10 cm and 10—15 cm soil layers increased significantly by 22.14%—63.91% compared to the soil matrix paths. Under 60 mm rainfall， the ion concentrations in the preferential flow paths of the 10—15 cm and 15—20 cm soil layers increased significantly by 54.98%—63.54% compared to those in the soil matrix paths. This demonstrated that preferential flow significantly promotes solute transport. Macropore flow showed a significant positive correlation with the coefficient of variation of solute concentration. The higher the proportion of macropore flow， the greater the difference in solute concentration across the soil layers. ［Conclusion］ Preferential flow was evident in the typical farmland soils in Hainan Province. The comprehensive evaluation index of the preferential flow increased with rainfall. The difference in solute concentration across the soil layers was greater with a higher proportion of macropore flow. The preferential flow paths significantly promote solute transport.