In　this　paper,　an　initial　boundary　value　problem　of　the　2D　incompressible　Benard　system　is　concerned.　The　global　existence　of　a　unique　strong　solution　is　established　by　the　energy　method　and　a　key　logarithmic　interpolation　inequality.　In　particular,　the　exponential　decay　rates　for　the　gradients　of　velocity　and　temperature　field　are　obtained.