The numerical solution of the double diffusive mixed convection phenomena around a heated cylinder in an enclosure was presented.The heated cylinder is located at the center of the enclosure with high temperature and concentration.The inlet flow with low temperature and concentration is located on the lower-left wall of the enclosure,and the exit is on the upper-right wall.Other walls are assumed to be adiabatic.The influences of Lewis number Le,buoyancy ratio Br and Richardson number Ri on the double diffusive mixed convection were investigated.Streamlines,isotherms,isoconcentrations,as well as the local and average Nusselt number and Sherwood number under different parameters were reported to characterize the mixed convection in an enclosure.