A deconvolution method for electron energy loss spectrum of diatomic molecules is proposed.Fitted energy positions are locked on accurate spectroscopic data.Calculated Franck-Condon factors are adjusted by a quadratic function.Precision requirement for Franck-Condon factors is reduced.Undermined parameters in deconvolution procedure are reduced dramatically.Precision of fitted results is improved. Optimized algorithm in fitting procedure avoids a lot of integral calculations.The program is used to deconvolve electron energy loss spectrum of H_2.Vibrationally resolved optical oscillator strengths are determined.The results agree well with previous experimental and theoretical studies.