To　tailor　the　morphology　and　performance　of　membrane　precisely,　exploring　the　principle　in　the　phase　separation　process　of　a　certain　polymer　is　a　crucial　step.　In　this　work,　a　novel　polysulfate　(PSE)　was　employed　to　fabricate　a　hollow　fiber　membrane　via　NIPS　method　for　use　in　ultrafiltration.　The　PSE　concentration　in　the　dope　was　varied　to　thoroughly　investigate　the　phase　separation　process　from　both　thermodynamic　and　kinetic　aspects.　The　dimension　and　skin　morphology　of　the　PSE　hollow　fiber　was　tuned　by　altering　air　gaps　during　spinning　to　receive　a　better　ultrafiltration　ability.　The　optimized　PSE　hollow　fiber　achieved　a　pure　water　flux　of　83.2　L˙m−2˙h−1　(LMH),　a　BSA　rejection　of　97.9%,　and　a　flux　recovery　rate　of　92%,　demonstrating　that　PSE　is　a　novel　polymer　with　a　promising　application　in　ultrafiltration　hollow　fiber　membrane.　©　2022