The influence of low temperature(11~15℃) on a two-sludge denitrifying and phosphorus removal system was studied in this experiment, the system is named AAO-biological aerated filter (BAF), which treats about 45m³ urban wastewater per day. The nitrification of this system recovered from the inhabitation of low temperature in a short time, however, the nitrification of AAO system which is running in the same condition with the AAO-BAF system was inhibited by the low temperature for a long time. The inhibition of low temperature on nitrification leads to the decline of phosphorus uptaking in the anoxic phase of this system, TP concentration in the effluent of anoxic phase rise from 1to 4mg/L, however, its aerobic phase can uptake the surplus phosphorus. The retention time of nitrifying bacteria is the main reason that leads to the difference of nitrification between the AAO and AAO-BAF according to the batch experiments. At 11, 16, 21, 27, 32℃, anaerobic phosphorus release rate of the sludge in the AAO-BAF system was 6.745, 8.378, 13.218, 11.513, 9.726mgTP/(h·gMLSS) respectively; The phosphorus removal rates during the anoxic reaction was 1.668, 1.892, 2.496, 2.835, 2.976mgTP/(h·gMLSS) respectively, the NO₃^--N removal rate was 0.786, 1.112, 1.761, 2.614, 3.464mgNO₃^--N/(h·gMLSS) respectively.