Abstract: The adsorption of polydisperse polymers at solid-liquid interfaces is studied by Monte Carlo simulations based on a lattice model.Apparent different conformations are found in the two polydisperse systems.The concentrations of tails,trains and loops in different layers are much lower in normal distribution systems than those in average ones,whereas the change of polymer conformation is more sensitive to temperature and the concentration of the total polymer segments in average distribution systems than that in normal ones.Simulation results also indicate that the concentration of tails in layers which are far away from the adsorption interface increases,while the concentrations of trains and loops decrease rapidly with the increase of temperature.This reveals that more stand-up conformations exist near the adsorption interfaces.This work also suggests that quantitative system errors are likely to be committed if monodisperse models are used to evaluate the real polydisperse polymer systems.