In this paper, graphene/CdTe quantum dots composites had been successfully synthesized, the spectral properties of the interaction between Brilliant blue and graphene/CdTe quantum dot complexes were investigated based on the strong fluorescence quenching effect of Brilliant Blue on graphene/CdTe quantum dots composites. Results shown that the UV absorption spectra of Brilliant Blue overlapped with the fluorescence emission spectrum of graphene/CdTe quantum dot composites, and increasing of fluorescence emission intensity of Brilliant Blue and the decreasing of the fluorescence emission intensity of graphene/CdTe quantum dot complex, all these indicated that fluorescence resonance energy transfer between Brilliant Blue and graphene/CdTe quantum dot has been taken place. Also there is a good linear relationship between the decreasing of fluorescence intensity of graphene/CdTe quantum dots composites (F₀/F) and the concentrations of Brilliant Blue, the linear range is 18.93?94.65nmol·L^-1, the detection limit is 6.6nmol·L^-1, which could be used to quantitative analysis of Brilliant Blue solution, and could provide a theoretical and experimental basis for new fluorescence sensors.