Lignin multilayer films were fabricated from salt-added lignosulfonate（SL） and poly（diallyldimethylammonium chloride）（PDAC） by the electrostatic layer-by-layer self-assembly,and the effect of salt on the SL/PDAC self-assembly was studied in this work.The self-assembly process was monitored by means of UV-vis spectroscopy,and the surface morphology of the films was observed via AFM.The results show that both the ionic strength and the salt species of the SL dipping solutions greatly influence the adsorption characteristics of SL during SL/PDAC self-assembly.When NaCl is added,the adsorbed amount of SL increases,the adsorption rate reduces,and the surface roughness of the SL/PDAC self-assembled films increases with the increase ionic strength in the investigated range.At the same ionic strength,the adsorbed amount of SL increases with the cation radius when LiCl,NaCl or KCl is added,while it decreases with the increase anion radius when NaCl,NaBr or NaI is added.