For the structural-acoustic radiation optimization problem under external loading,acoustic radiation power was considered to be an objective function in the optimization method. The finite element method(FEM) and boundary element method(BEM) were adopted in numerical calculations,and structural response and the acoustic response were assumed to be de-coupled in the analysis. A genetic algorithm was used as the strategy in optimization. In order to build the relational expression of the pressure objective function and the power objective function,the enveloping surface model was used to evaluate pressure in the acoustic domain. By taking the stiffened panel structural-acoustic optimization problem as an example,the acoustic power and field pressure after optimized was compared. Optimization results prove that this method is reasonable and effective. For the structural-acoustic radiation optimization problem under external loading, acoustic radiation power was considered to be an objective function in the optimization method. The finite element method (FEM) and boundary element method (BEM) were adopted in numerical calculations, and structural response and the acoustic response were assumed to be de-coupled in the analysis. A order algorithm for used in the strategy in optimization. In order to build the relational expression of the pressure objective function and the power objective function, the enveloping surface model was used To evaluate the pressure in the acoustic domain. By taking the stiffened panel structural-acoustic optimization problem as an example, the acoustic power and field pressure after optimized was compared. Optimization results prove that this method is reasonable and effective.