Preview control is to use forward road information acquired from preview sensors in designing a controller. Preview control which is composed of feedback and feed-forward input can lead to better performance than feedback control alone. Application of the preview control based on the active suspension to tracked vehicles will be introduced. In previous papers of mine, preview controllers which include actuator dynamics and linear interpolation technique of acquired road information to compensate for varying speed of vehicles respectively were designed. In this paper, design of 3D. preview control and its application to a 3D. tracked vehicle model will be covered. Moreover, generation of preview information during turning motion will be described. From simulation results using a special road condition, RRC 9, performance enhancement will be shown using ISO 2631 in terms of ride comfort under assumption that actuators are ideal and the velocity of the vehicle is constant. Finally, based on the analysis of turning motion in steady state along circular path, a method to reduce the error between preview information and traveling trajectory for each road wheel will be suggested.