In order to successfully reduce the weight of a machine or structural part it is possible to optimize the material parameters or to use alternative advanced materials instead of conventional engineering ones. Helical springs, important machine parts, are used for vibration damping in machines and are generally made of steel. As an alternative to helical steel springs in scope of the work, mechanical behaviors of helical springs made of carbon nanotube additive epoxy composite reinforced with carbon fiber have been investigated. First, mechanical properties for matrix resins with variable addition rates of CNT have been determined by using micromechanics approaches. In the study, mechanical behaviors of composite springs have been examined both analytically and numerically; numerical part of which ANSYS software based on finite elements methods has been exploited. In the book, the effects of spring wire diameters and particle additive rates into resin on the mechanical behaviors of composite springs have been investigated. The study indicates that helical springs made of CNT additive epoxy composite can be replaced instead of steel ones considering the specific point of view.