Desalination and concentration of cephradine mother liquor were investigated with NF270, NF90 and DL nanofiltration membranes, NF270 is suitable for desalination of cephradine mother liquor.The effects of direct concentration and pre-concentration-diafiltration-concentration on nanofiltration process were investigated resp., and various cleaning methods were used to recover the membrane flux.The produce ratios of cephradine by 2-naphthol chelation from concentrated liquor and original liquor were compared.The results showed that direct concentration would result in a rapid decrease in membrane flux and could not realize the desired concentration effect.Pre-concentration-diafiltration-concentration mode was much suitable one to concentrate the cephradine mother liquor.Using the cleaning agent containing alkali, the fouled membrane could be almost recovered.The produce ratio of cephradine from concentrated liquor was larger than that of original one.