This paper presents the study of traffic load variations effect on the dynamic analysis of cable-stayed bridges. Time histories of displacement, velocity, acceleration, normal force, and bending moment are presented for different traffic load speeds. This study is concerned with harp bridges having five spans considering single plane of cables with 140 m for exterior spans, and 280 m for interior spans. The total length of the bridge is 1120 m. The own weight of all structural elements, and traffic load including impact are taken into account. In the dynamic analysis, the energy method, based on the minimization of the total potential energy (TPE) of structural elements, via conjugate gradient technique is used. The procedure is carried out using the iterative steps to acquire the final configuration. All prepared computer programs in FORTRAN language for this work and their verification is written by [1]. The conclusion, which have been drawn from the present work are outlined.