The purpose of the paper is to test the toxicity of the plant molluscicide “ Lo-wei ” to zebra fishes ， Japanese quails and freshwater shrimps in laboratory to evaluate its impact on the environment ． According to the rightful test conditions ， the toxicity range of the molluscicide on the zebra fish ， Japanese quail and freshwater shrimp was previous tested ． In the rightful test we set different molluscicide concentrations by a certain percentage in this range ， with 3 time repeat tests for each concentration ， and a set of contrast test ． When “ Lo-wei ” powder (TDS) concentration in 4 percent is higher than the safe level of plant molluscicide LC₅₀ value, it generates a moderate toxicity to birds and shrimps, little effect to birds actually and a greater risk to fishes ．