The effect of concentration of 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) yellow dye in solution on fluorescence performance was studied through various concentrations. Also the photoluminescence (PL) spectra of rubrene solution with various concentrations were measured to investigate the concentration effect, which is beneficial to obtaining an optimum concentration at maximum PL intensity without concentration quenching. One hand was to focus on the range of concentration for quenching. The other hand was to change the solution concentration in the range of concentration. The results showed that the PL intensity was the highest at a rubrene concentration of 2×10-3 mol·L-1, which was fixed on a concentration range from 10-3 to 10-2 mol·L-1. And it was decreased only 11% with the increase in concentration after the optimum concentration. The PL spectra of rubrene: N,N’-Bis(naphthalen-1-y)-N,N’-bis(phenyl)benzidine (NPB) blending system with various proportions in solution were also measured, indicating that the inefficient energy transfer between NPB and rubrene leads to white fluorescence light emission. It was better to realize blue and yellow fluorescence from NPB and rubrene, so the white light was obtained.