According to the principle of total reflection theory and the prism coupling, the simultaneous measurement of the refractive index of the prism and waveguide refractive index of film material and thickness are measured. Highly collimated diode laser is used to enter to the boundary surface of the waveguide film inside the prism, the prism coupler M line is obtained by gradually rotating the prism or changing the angle of incidence of the prism, the lines of previous trough are waveguide mode excitation in the M line ending at the left side there is an incomplete crest, its reflected light intensity decays rapidly with the angle of incidence, which is the total reflection critical point, by this the simultaneous measurement of the parameters of the prism and the waveguide film is realized; refractive index of the prism coupler integrated planar waveguide prism and the refractive index and thickness of the polymethylmethacrylate (PMMA) polymer waveguide film are measured with this method, measured prism refractive index accuracy is ±1.9×10－4. The accuracy of the waveguide refractive index and thickness are ±6.2×10-4 μm and ±1.6×10-2 μm respectively.