In the present paper, a method for how to design a portable UV-Vis spectrophotometer is introducect. The Hamamatsu multichannel detector S3904-1024Q and a flat field concave grating are employed to design a miniaturized dispersion system In order to solve the contradiction between the spectral width and energy-utilizing ratio of the light source, a multi-band optical fiber is employed, one side of which is arranged to be rectangle as the entrance slit. The touch screen is employed as the input and output system of the spectrophotometer, and the miniaturized fiber-optic UV-Vis light source is employed as the light source. The research results and testing results of the prototype show that the new spectrophotometer based on the authors' new method is of miniaturization in volume(190 mm X 170 mm X 100 mm), can realize multi-wavelength-detection on-line, and is easily handled (touch screen control), and its performance accords with the Chinese national standard.
