Abstract: Applying the methods of molecular quantitative structure-activity relationships(QSARs)on the research of ecological toxicology is an important area and precedent tide,and the QSAR applies many kinds of mathematic models and molecular characteristic descriptors to explore the ecological biotoxication mechanisms at the level of biochemistry moleculars.This paper discusses some available metods of establishing molecular structure-effect relationship,and effectively applies some molecular descriptors to investigate the biotoxication on some substituent aromatic hydrocarbons.