Information on the microcharacteristics of soil pores under raindrop splash is essential for understanding various soil processes. However, there is still a lack of research on the quantification of soil pore microstructure and the impact of raindrop splash on soil microstructure. The changes in the surface soil pore microstructure of Loessial soil and Lou soil under splashing with three different raindrop diameters were analyzed quantitatively and visually by rainfall experiments and synchrotron radiation microcomputed tomography (SR-mu CT). The present findings show that in rainfall erosion, the shape, number, distribution and connectivity of pores are affected by the diameter of raindrops and soil type. The pore shape index increases with decreasing particle size. As the main channels for soil moisture transport, large and medium-sized pores tend to be elongated and irregular in shape. With increasing raindrop diameter, the overall quantity of pores and the number of micropores (<= 25 mu m) of Loessial soil and Lou soil increased, while the total porosity and the number of macropores (>1000 mu m) decreased. Under the same raindrop diameter, the number of pores grew as the pore diameter decreased, and the number of micropores was significantly (p < 0.05) greater than that of other pore sizes. There was a very strong positive correlation (p < 0.01) between total porosity and macroporosity and a strong negative correlation (p < 0.05) between total porosity and microporosity. The specific surface area (SSA) and plugging ratio (PR) of the two soils increased with increasing raindrop diameter. The PR of Loessial soil and Lou soil under 4.05 mm raindrop splash were 30.48 % and 34.25 %, respectively. The above research shows that raindrop splashing causes the dispersion and migration of soil particles, resulting in pore plugging, which creates a material basis for the formation of soil surface crust and the slowing of infiltration.