Abstract: In order to study the adsorption behavior of polycyclic aromatic hydrocarbons (PAHs) on sediment of the Yellow River in the Lanzhou section, naphthalene (Nap) was selected as the target pollutant to understand the adsorption kinetics and thermodynamics of Nap onto sediment based on the batch experiments. Meanwhile, the influence of initial concentration, particle size, pH value, ionic strength and other factors on the adsorption process of Nap on the sediment of the Yellow River in the Lanzhou section was also investigated. The results indicated that the adsorption kinetics of Nap onto sediment could be best described by the pseudo-second-order-model, and the adsorption process was mainly divided into two stages:fast adsorption (0-4 h) and slow adsorption (4-8 h), reaching equilibrium at about 8 h, indicating that the adsorption process is controlled by a variety of factors. The adsorption thermodynamics of Nap onto sediment was fitted well with the Freundlich model. At a temperature of 25℃ to 45℃, average adsorption free energy (E) of 0.288-0.316 kJ/mol, E < 8 kJ/mol, the Gibbs free energy (ΔG^θ) was less than zero, and Enthalpy (ΔH^θ) and Entropy (ΔS^θ) were greater than zero in the adsorption process, which showed that the adsorption of Nap on sediment is a spontaneous and endothermic process with an increase in randomness, and is dominated by physical adsorption. The analysis results of the influencing factors showed that:the smaller the particle size, the greater the adsorption capacity toward the Nap; as the ionic strength increased, the adsorption amount of Nap was decreased; when the initial concentration increased, the adsorption capacity also increased; and strongly acidic conditions inhibit the adsorption process, while an alkaline environment promotes the adsorption process. The desorption amount of Nap from the Yellow River sediment in the Lanzhou section was much less than the amount of adsorption, indicating the phenomenon of desorption hysteresis. The results show that the adsorption rate of naphthalene in sediments of the Yellow River in Lanzhou section is affected by both internal diffusion, surface adsorption and liquid film diffusion, and the adsorption process is affected by both the particle size of the sediment and the pH and ionic strength of the solution.