A convective cooling platelet structure is a considered as thermal protection system to prevent the leading edge of airfoil from the serious aerodynamic heating. The cooling effect parameter is proposed in this paper. By the use of fluid structure interaction method, the cooling effect of convective cooling structure is investigated under given condition. The minimum that is 0.25 when the coolant is water occurs on the leading edge of airfoil head. The research shows that the increases with the increase of channel aspect radio () and reaches a stable value that indicates that the cooling effect is saturated. Situation unfavorable for cooling may occur if the keeps increasing. And the decreases with the radio of airfoil's head decreasing. With coolant flux increasing, the also increases to a stable value and the pressure drop between inlet and outlet increases rapidly when the structure and the material of the convective cooling platelet structure are fixed. Considering the pressure brought to the supply system due to the increase of flux, we should choose the optimal coolant flux value in order to obtain better cooling effect. Both the inner coolant groove and the external refractory protection should be of high thermal conductivity material which can strengthen the heat transfer of structure and enhance the cooling effect.