The key to study the sediment deposition of the Yellow River is to clarify the sediment transport characteristics of the erosion sediment on the Pisha Sandstone slope. The physical simulation technology of water, wind and freezing-thawing composite erosion was used to study the variation characteristics of erosion sediment particles on Pisha Sandstone slope under the composited action of three groups of different erosion dynamics, which were single water erosion, freezing-thawing water erosion, and freezing-thawing wind water erosion, under the condition of 35° slope and 110 mm/h rain intensity. The results showed that the Pisha sandstone slope was dominated by overall erosion under single water erosion action, and the erosion sediment particles changed stably. Under the action of freezing-thawing water erosion, coarse particles were produced obviously, and the effect of freezing-thawing on coarse particles was prominent. The slope stability was the worst under freezing-thawing wind water erosion, and the change of erosion sediment particles was the most drastic. In the process of slope erosion under composite erosion, sediment particles with larger diameter were mainly transported. The fluctuation of erosion sediment particles with the increase of erosion dynamics changed dramatically.