Abstract: In order to search for a feasible toxicity assessment assay for coal pyrolysis wastewater,based on typical toxic cyclic pollutants in coal pyrolysis wastewater,three common species were applied to investigate effect of light conditions and sample color on the tests,as well as their applicability in real coal pyrolysis wastewater.The results showed,as light and color highly affected the toxicity evaluation of typical pollutants,it was suggested that the toxicity should be tested in dark conditions,and testing methods characterized by absorbance should be avoided.Finally,algae test was not suggested for toxicity evaluation of coal pyrolysis wastewater,while Daphnia magna (D.magna) was suggested for application due to the highest applicability in the real coal pyrolysis wastewater evaluation with TU was 100.87,12.13 and 8.37 for effluent from anaerobic,aerobic,advanced oxidation process,respectively.And Tetrahymena thermophile (T.thermophile) may be an alternative toxicity test for aerobic wastewater with TU=6.67,similar to D.magna.