Abstract: The relationships betweer the molecular structures of organic substances and the fluorescence generation are studied. According to this theory, the molecular structures of a few common carbamate pesticides such as carbaryl, carbofuran and propoxur etc are analyzed and their fluorescence characteristics are revealed, and that the mechanism of fluorescence generation of carbamate pesticides is ascertained. It provides a theoretic basis for detecting carbamate pesticides by means of a fluorescence analytical method. Moreover a steady-state fluorescent spectrograph is applied to conduct fluorescence spectrum experiments with standard carbaryl liquor and carbofuran liquor.The results indicate that carbamate pesticides may emit fluorescence as being excited under the condition of a certain solvent, and that it is feasible to detect carbamate pesticides by fluorescence spectral analysis.