Abstract: Gulonic acid ultrafiltration concentrate was further concentrated using ceramic membrane, and the effects of operating pressure, temperature, concentrating time and volume of washing water on the membrane flux and gulonic acid yield in further concentration were investigated.Besides, membrane fouling and cleaning method were also studied.The results showed that the back calculated yield was 96.9%, the acid content of filter residue reduced to 1 /10 of the feed and the total residue was about 3% after 3 times further concentration, when the operating pressure was around 0.30MPa, the temperature was about 40℃, and the volume of washing water was 0.67 times that of feed liquid.Average membrane flux maintained at 24.5²6.5LMH for the whole process, which was suitable for the real industrial production.Moreover, gulonic acid didn't cause irreversible pollution to ceramic membrane during experimental period. The flux of the ceramic membrane could be fully recoverd after washed by the commercial alkaline cleaner.