Abstract: In order to study the adsorption behavior of the intertidal sediment adsorption of polycyclic aromatic hydrocarbons (PAHs), we use the Soxhlet extraction method, characteristic ratio method, statistical analysis, isothermal adsorption experiment, together with sediment adsorption parameter modeling and inverse calculations for three different particle size groups (i.e., 0～31 μm, 32～64 μm, and ＞ 64 μm) to identify the influence of particle size on the adsorption parameter. The results reveal that the contents of PAHs varied from 49.67～141.90 ng·g⁻¹, with an average of 74.92 ng·g⁻¹. The PAHs were primarily trinuclear, tetracyclic or pentacyclic, and the surface sediment PAHs in the study area had a mixed origin of combustion. When the organic matter content in sediments is relatively low, particle size plays a major role in PAHs adsorption.