Suspension spring system was taken as research object. The non-dimensional dynamic equation of dropping impact of the system was solved by variational iteration method. The first-order approximate analytical solutions such as non-dimensional displacement and non-dimensional acceleration were obtained. Analytical solutions of non-dimensional peak displacement, non-dimensional peak acceleration, and dropping shock extended period were obtained and compared with Runge-Kutta method. The results showed that the non-dimensional acceleration response-time curves agree well, and relative errors of non-dimensional acceleration peak value and dropping shock extended period are less than 4% and 2% respectively. The damage evaluation equation combined with system parameter, product fragility, non-dimensional dropping velocity and suspension angle was established. System parameter and dimensionless dropping shock velocity were selected as two basic evaluation quantities, and dropping damage boundary curves were obtained. Curved surface of dropping damage boundary was obtained by using dimensionless dropping shock velocity, system parameter, and initial suspension angle as basic evaluation quantity. The results showed that the system security performance increase with decrease of suspension angle; the suspension geometry nonlinear system characteristics is superior to the linear system in product protection. The purpose was to provide reference for suspension spring system design.