The acute toxic effect of malachite green, furazolidon, mixture ofcopper sulphate and ferrous sulphate (ratio 5:2), common table salt, methylene blue andheavy metals such as Hg, Cd, Cu and Zn on larva of crucian carp, Carassius auratusgibelio were determined with static bioassay test. The experimental results showed thatthe safe concentrations of 4 kinds of chemicals to fish disease (except methylend blue)were 0.012, 32.900, 0.680 and 870 ppm, respectively. The safe concentrations of 4 kindsof heavy metals(Hg, Cd, Cu and Zn) were 0.0006, 0.0113. 0.0270 and 0.0950 ppm,respectively.