Abstract: UniFed SBR process has the unique feature which is the introduction of the influent into the settled sludge blanket during the settling and decant periods of the operation.It achieved suitable conditions for denitrification and anaerobic phosphorus release and also had high rate of nitrogen and phosphorus removal.In our experiment,this type of UniFed SBR process for treatment of domestic wastewater was used to study the effect ofρ(C)/ρ(P)ratio,decant ratio,maximal removal of phosphorus loading and aeration intensity on removal of phosphorus.Resultsshow that whenρ(C)/ρ(P)ratio is 23,the removal efficiency of TP is 94.67 %.When the ratio ofρ(C)/ρ(P)is higher than 23,the concentration of phosphorus in the effluent is 0 kg/m³.when the carbon source become the limiting factor to phosphorus release,the higher decant ratio is, the lower phosphorus concentration in the effluent is.When the carbon source is adequate,the system is proved to have a reliable performance in phosphorus removal.This system has great effect on phosphorus removal in domestic wastewater,which provides a new method to enhance biological phosphorus removal.