Abstract: Lattice Boltzmann method is adopted to investigate the characteristics of double-diffusive natural convection around a heated cylinder in square enclosure with coupled Soret and Dufour effects. The inner heated cylinder is located at the center of the enclosure and four surrounding walls are assumed to be low temperature and concentration. With different parameters of buoyancy ratio Br (-5 ≤ Br ≤ 5), Soret number Sr (-0.4 ≤ Sr ≤ 0.4) and Dufour number Df (-0.4 ≤ Df ≤ 0.4), the double-diffusive natural convective characteristics in the enclosure are analyzed. The results show that, at the same Br, and with the simultaneously increasing Sr and Df, both the heat and mass transfer capacities are weaken. At the same Sr and Df, the heat and mass transfer capacities are first weakened and then enhanced as Br increases. The simulation study of this physical model can provide the theoretical support for the analysis of indoor fire and pollutant diffusion.