A new method of the fluorescent detection is introduced to use for detecting glucose molecule marked by fluorescence in microchannels. The fluorescent detection for glucose molecule is successfully realized in microchannels. The experiment results show that it is feasible to use sodium fluorescein marking the glucose molecule. At the same time, the experiment analyzes that experimental results have been influenced by wavelength of exciting light and acidity and basicity of solution. It is concluded that the glucose molecule marked with sodium fluorescein can be identified effectively in microchannels in this experiment. The new technology based on the study will lead to new application in bioanalysis and biological detection.