Na2O-CaO mixture smelter was used to fully decompose molybdenite and other insoluble ores. Interference elements were deposited twice to be separated and removed. Catalytic reduction polarographic wave produced by ReO-4 in presence of telluric acid was used to perform the test on tellurium addition and interference element. H2SO4-Na2SO4-Te base solution catalytic polarographic method was applied to determine trace rhenium in molybdenite using JP-2D polarograph, getting satisfying result.