OBJECTIVE： To investigate the effect of polyamide on the separation on phenolic acids components by nanofiltration process. METHODS： Phenolic acids components were selected as targets， extracted from the Salvia miltiorrhiza， Lonicera japonica or intermediate preparations （tea polyphenols） with water， and filtered with membranes with different pore sizes. The content changes of components were analyzed by HPLC. RESULTS： Danshensu， protocatechuic aldehyde and caffeic acid could better transmit nanofiltration membranes with 3 different pore sizes； with the decrease of pore size， the rejection rates of neochlorogenic acid， chlorogenic acid， rosmarinci acid， ECG and EGCG grew in different levels. But salvianolic acid B was almost retained by the membrane with low molecular weight except 600-800 Da. CONCLUSIONS： Molecular weight importantly influenced nanofiltration separation on phenolic acid components； nanofiltration has a good prospect in enrichment of phenolic acids components.