Rubrivivax　gelatinosus　cultivated　in　wastewater　environment　can　combine　the　biomass　resource　recycling　for　generating　chemicals　with　sewage　purification.　However,　low　biomass　accumulation　restricts　the　exertion　of　this　advantage.　Thus,　this　paper　investigated　Fe3+　advancement　for　biomass　production　in　starch　wastewater　under　light-anaerobic　condition.　Results　showed　that　addition　of　Fe3+　was　successful　in　enhancing　biomass　production,　which　certainly　improved　the　feasibility　of　biomass　recycling　in　R.　gelatinosus　starch　wastewater　treatment.　With　optimal　Fe3+　dosage　(20　mg/L),　biomass　production　reached　4,060　mg/L,　which　was　1.63　times　that　of　control　group.　Amylase　activity　was　improved　by　48　%.　Both　COD　removal　and　starch　removal　reached　90　%.　Hydraulic　retention　time　was　shortened　by　25　%.　Proper　Fe3+　dosage　enhanced　biomass　production,　but　excess　Fe3+　was　harmful　for　biomass　accumulation.