Abstract: A fluorescence spectrometer which can measure pesticide concentration is designed by using a xenon lamp as excitation lightsource，employing optical fibers to transmit and detect fluorescence and combining with CCD spectrumdetermination technology based on fluorescent characteristics of carbaryl that can emit fluorescence as it is excited by UV rays.Moreover,the rapid measurement of carbaryl residues in cucumbers is implemented with a steadystate fluorescent spectrograph and the new system respectively. The results indicate that the linear concentration range is 0.0～120.0μg／L for carbaryl, the detection limit (LOD) is 5×10-7μg／L，the linear correlation coefficient r is 0.9991 as the excitation wavelength is 319nm and the fluorescence emission wavelength is 647nm. The data prove up to the hilt that the instrument meets the demand of fluorescence detection.