The present paper investigates a problem related to improving the dynamic characteristics of a truss structure with the goal of avoiding certain dynamic problems. The procedure is based on the analysis of the distribution of potential and kinetic energies in all elements of a truss structure. These energies would in turn give a prediction of the elements that needs to be re-analyzed and eventually removed. The resulting truss would be an optimized structure that has an improved dynamic behavior with respect to its natural frequencies. The Reanalysis technique based on structural dynamic modification (SDM) is accomplished using Finite Element Method (FEM). To this end, an algorithm has been built, based on FEM, to obtain the distribution of kinetic and potential energies in the truss elements. Seeking the optimum condition of design, the main aim of the dynamic modification is to increase the natural frequencies and increase the spacing between them. An example illustrating the efficiency of the procedure is demonstrated and the results has proved the goal of the proposed methodology.