The　different　effects　of　additional　aerobic　granules　(AGs)　and　phosphorus　removal　granules　(PRGs)　on　the　start-up　and　stable　operation　of　partial　nitrification　granular　sludge　(PNGS)　were　compared　at　room　temperature(22-28).　The　results　showed　that　in　the　first　stage　(days　0-22),　partial　nitrification　was　accomplished　on　day　19　for　the　three　reactors　(R1,　R2,　and　R3).　In　the　second　stage　(days　23-56),　20%　AGs　and　20%　PRGs　were　added　to　R2　and　R3　to　induce　PNGS.　The　start-up　of　the　granules　of　the　three　reactors　was　successfully　achieved.　The　mean　particle　sizes　of　R1,　R2,　and　R3　reached　412　μm　at　day　76,　468　μm　at　day　42,　and　400　μm　at　day　56.　In　the　third　stage　(days　57-108),　because　the　influent　ammonia　load　increased　from　0.4　kg•(m3•d)-1　to　0.5　kg•(m3•d)-1　and　the　COD　load　increased　from　0.2　kg•(m3•d)-1　to　0.5　kg•(m3•d)-1,　the　mean　particle　sizes　of　R1　and　R2　increased　significantly.　The　average　particle　sizes　of　R1　and　R2　reached　689　μm　and　893　μm　by　the　end　of　the　operation　(day　108),　but　sludge　expansion　occurred　in　R3.　The　inoculation　of　either　AGs　or　PRGs　could　quickly　achieve　granulation,　but　the　PNGS　inoculated　with　the　AGs　could　adapt　to　higher　C/N　and　be　more　tolerable　to　shock　loads　and　long-term　stable　operation.　©　2018,　Science　Press.　All　right　reserved.