Аннотация:This paper presents a new internal reference method for studying the upconversion luminescence of nanoparticle suspensions. The method provides correct analysis and comparison of luminescent signals obtained under different conditions. For excitation of the signal it is proposed to use the radiation of optical parametric oscillator at two wavelengths in order to simultaneously excite the upconversion luminescence of nanoparticles and the Raman signal of the medium in the Stokes region. Raman signal plays role of internal reference which allows to eliminate the influence of the instability of excitation intensity, inaccuracy of experimental setup adjustment etc. on the result of measurements.