Performance Assessing and operational maintenance of Yue-Jin Harbor Sewage Plant (Project no.TNEPB-101-WS-30529) was authorized Chi-Chiang Environmental Eng. Co. by Environmental Protection Bureau of Tainan City Government. This 3-man project is about waste water and trash treatment, public health and other environment protection service and implementing member include Main manager Dr. Hou-Da Chuang , one operator and one material writer. Project outlay is 1,060,000 NTD and takes 8 and half months from November 1, 2011 to August 31, 2012. Report of Yue-Jin project official named "Performance Assessing and operational maintenance of Yue-Jin Harbor Sewage Plant" all has 214 pages written by transitional chinese and using PDF format. Total amount of treated waste water were 141,158 cubic meters. The average waste water flow rate is 553 CMD. The average influent BOD5 concentration was 24.3 mg/L. The average effluent BOD5 concentration was 7.73 mg/L and the BOD5removal efficiency was 68.2%. The average influent COD concentration was 66.91 mg/L. The average effluent COD concentration was 33.06 mg/L and the COD removal efficiency was 50.6%. The average influent SS concentration was 25.01 mg/L. The average effluent SS concentration was 10.9 mg/L and the SS removal efficiency was 56.4%. The cost of waste water treatment is in the range of 5.37 to 13.17 NT dollars. Keywords: Yue-Jin Harbor, Performance Assessing and operational maintenance, removal efficiency.