Ultrafiltration　(UF)　using　hollow-fiber　membranes　is　being　developed　in　the　field　of　drinking　water　purification.　In　China,　surface　water　is　polluted　in　some　regions　where　an　advanced　treatment　facility　should　be　constructed　to　produce　safe　drinking　water.　However,　it　is　limited　because　of　some　problems　associated　with　its　direct　use,　which　includes　membrane　flux　decline　and　insufficient　removal　of　dissolved　organic　matter.　This　study　examined　the　effect　of　pretreatment　by　coagulation　and　rapid　sand　filtration　on　membrane　performance.　An　ultrafiltration　system　with　a　capacity　of　120　m(3)/d　was　constructed　to　purify　raw　water　taken　from　the　Songhuajiang　River　near　Harbin　in　northern　China.　Studies　showed　that　independent　of　raw　water　turbidity,　the　membrane　permeate　water　turbidity　is　always　below　0.2　NTU.　The　reduction　of　organic　matter　was　satisfactory　with　CODMn　31-42%　removal,　DOC　42-47%　removal　and　UV254　22-29%　removal.　Pretreatment　with　coagulation　not　only　improved　the　treated　water　quality,　but　also　enhanced　membrane　performance,　that　is,　the　permeate　flux　increased　and　flux　decline　was　reduced.