As the development of semiconductor industry is escalating, many environmental issues have emerged dramatically as well. In the future, the Taiwan Environmental Protection Agency (EPA) should set a standard for the discharge of the wastewater from semiconductor industry. Since then many semiconductor manufacturers have to find ways to deal with the problem. Therefore, acute toxicity of the semiconductor manufacturing wastewater was examined. In this study, Daphnia magna immobility test was employed to detect the wastewater and effluent of semiconductor manufacturing process. The LC50 is 100, 5.34 and 6.91% for CMP wastewater, CMP-mixed acid-alkali wastewater, and effluent on D. magna, respectively, and TUa is <1、18.72 and 14.47, meaning that the toxicity risks is ‘’very toxic’’.