MEH-PPV film is a kind of conjugated polymers synthesized by modified Gilch route. The reflection spectrum of MEH-PPV film was measured by the UV-365 spectrophotometer, which is not exact result of the film because of the reflection of glass substrate. A similar formula annulled the influence of the glass was given, and in this way modified reflection spectrum was figured. With the data of the modified spectrum and the Kramas-Kronig relation, the refraction index of MEH-PPV as a function of wavelength was given. The reflection spectrum is calculated by the Fresnel formulae and the calculated refraction index data in order to compare the measured result of reflection spectrum with the computed result, in which little errors resulted from the method of calculation and the influence of the glass substrate are shown. In addition, the measured absorption spectrum shows a broad peak from 450 nm to 600 nm approximately corresponding to the peak of the curve of refraction index at 550 nm. From those results the calculated refraction indexes are basically resonable and exact.