Based　on　Michelson　interferometer　principle　and　controlled　via　an　elaborately　designed　computer　program,　the　variation　of　interference　order,　which　contains　the　information　of　refractive　index　and　its　variation,　can　be　detected　by　an　optical　power　meter　and　a　CCD　camera.　According　to　the　relation　between　the　increment　of　interference　order　and　the　change　in　optical　path　difference,　the　refractive　index　of　photopolymer　samples　can　be　calculated　in　an　accurate　way.　Typical　measurements　of　the　refractive　index　of　our　photopolymer　samples　are　1.547　and　1.583　at　wavelength　532nm　and　457　nm,　respectively.