The purpose of this study is to survey the phosphorus behavior and its chemical forms in the municipal sewage treatment processes. Samples for analysis were taken from Cheongju sewage treatment plant once a month during the period from March to October in 1995. Total phosphorus inlet concentration into the sewage treatment plant is 3.95㎎/ℓ, and its fractions are TRP 57.8%, THP 22.2% and TOP 20.3%. TP concentration was increased about 50% higher than that of inlet concentrations by mixing with overflow from thickener and anaerobic digester. Suspended total phosphorus is removed about 42.8% in the primary settling tank, and phosphate fraction-DTP and STP-of inlet into the biological process is nearly same. The DTP removal is about 55% by the biological process. Total phosphorus concentration of the final effluent is 1.33㎎/ℓ, and it was found that the main forms were TRP(84.2%).