In the present paper the basic theory that organic molecules can emit fluorescence as they are excited by ultraviolet rays is described, the molecular structures of a few common pesticides, such as carbamate, benzoylurea and fungicide, are analyzed, and the mechanism of fluorescence generation is also ascertained. Consequently, the theoretic basis for further detection of pesticides by means of fluorescence methods is provided. Moreover a steady-state fluorescence spectrograph was applied to conduct fluorescence spectrum experiments with standard solutions of these pesticides, the fluorescence spectra were obtained, and their fluorescence characteristics were also analyzed. The results indicate that carbamate, benzoylurea and fungicide pesticides may emit strong fluorescence when excited by UV rays under the condition of a certain solvent, their fluorescence spectra are distinct, and the resolution is fine. As a result, it is feasible to carry out qualitative and the quantitative analysis of the concerned pesticides by fluorescence spectral analysis.