Abstract: Though the constrained layer damping can reduce the vibration effectively,it increases the weight and the size of the structure. Thereby anoptimization of the constrained layer damping treatment isnecessary. In this paper, a new model of the partial stand-off constrainedlayer damping patch is established in the finite element software ANSYS.Based on modal strain energy principles, the modal loss factor of theproposed model can be found. An objective function related tothe modal loss factors is constructed. Its design variables include thenumber, the length and the spacing between of damping patches, the thickness of thestand-off layer and the constrained layer. By using the multi-objective geneticalgorithm of MATLAB, the optimization is carried out. The results ofexamples show that after the optimization the constrained layer damping can reduce vibration more effectively with less additional weightand attenuate the vibration of the structure in a shorterperiod of time than before the optimization.