The DFT-B3LYP method, with the basic set 6-311G*[KG-*3]*, was employed to calculate the molecular geometries and electronic structures of 49 organic compounds. EHOMO, ELUMO, ΔE,ENHOMO,ENLUMO, ET, QH, Q-, μ and Vwere selected as structural descriptors. The anesthesia activity(log 1/C) of these compounds to tadpoles along with hydrophobicity described by log KOW, the above ten structural parameters, was used to established the quantitative structureactivity relationships (QSAR) by multiple linear regression. The R2, q2, SE and F for model (2) established in this study were 0.933 2, 0.930 1, 0.274 and 121.800, respectively. The result indicated that the model had good predictability. In light of the model, the toxic actions of organic compounds included two steps: one was the collection of the compounds in vivo, which was described by log KOW; the next was the electronic reactions between the chemicals and macromolecular compounds, which were represented by ELUMOand ENHOMO.
