The parameter design of a Intensity Modulation Spectropolarimeter(IMS) was studied and analyzed in this paper. The basic concept and structure of the IMS were described and the dependence on modulator design, spectrometer selection and system performance was analyzed. By taking an integrated system design for an example,the IMS experimental system was established in the laboratory, the basic concepts and characteristics of the technique were verified and the polarization spectra from a typical light source were also tested. Experimental results show that the polarized degree of the light from a tungsten-halogen lamp collimator is less than 10%, but it is about 100% when the light is polarized by a polarizer in the spectral range of 525-700 nm. These results are coincident with the theoretical results wel1,which verifies the feasibility of method that spectropolarimeter can be realized based on the intensity modulation.