Abstract: Based on mode strain energy used to calculate the mode damping dissipation factor, the method of mode strain energy sum is presented. The method is utilized to study the high strain energy sum zone of thin-wall box with partial coating damping layer, and the rules of influence of coating parameters versus structural damping dissipation factor are attained. Furthermore, by the introduction of localization-mode method, the structures local mode and maximum strain energy zone are regulated, which realizes the optimization of damping material placement. The research results show that synthetically using the method of mode strain energy sum and localization-mode can accurately find and control the distribution of high strain energy sum, which adds the placement flexibility of partial coating damping layer and also helps to reduce the structural mass.