This　study　focused　on　star-up　of　the　partial　nitrification　in　sequencing　batch　biofilm　reactor　(SBBR)　with　domestic　wastewater　at　room　temperature.　No　significant　nitrate　formation　was　observed　during　the　full　period　of　operation　and　the　nitrite　oxidizing　bacteria　(NOB)　was　successfully　outcompeted.　When　influent　ammonium　concentration　decreased　from　200mg/L　to　80mg/L,　a　stable　influent　at　a　ratio　of　1.03　NO2-N/NH4-N　was　produced　after　44　continuous　cycles　(33d)　and　that　indicated　partial　nitrification　achievement.　A　recommended　start-up　strategy　based　on　high　FA　concentration　and　aeration　control　was　proposed　to　achieve　partial　nitrification　with　low　ammonium　strength　wastewater　at　room　temperature.