The　approximation　technology　based　on　Kriging　model　is　applied　to　the　aerodynamic　optimization　design.　The　characteristics　of　the　optimization　method　based　on　the　approximation　technology,　the　traditional　gradient-based　search　algorithm　and　the　standard　genetic　algorithm　are　studied,　through　calculating　global　extreme　of　two　test　functions　and　re-constructing　the　geometry　of　airfoil.　The　result　shows　that　the　optimization　method　based　on　approximation　technology　has　good　global　performance　and　also　can　greatly　save　the　calculating　resources.　This　method　is　applied　to　the　aerodynamic　optimization　design　of　airfoil,　defining　the　lift-drag　ratio　as　the　goal　function,　when　Mach　number　is　0.7　and　the　angle　of　attack　is　3°.　The　application　indicates　that　the　lift-drag　ratio　of　optimized　airfoil　is　increased　by　81%　comparing　with　the　original　airfoil,　and　the　cross　section　area　of　the　optimized　airfoil　is　decreased　less　than　1%.