Multi-body Dynamics simulation of tracked vehicles is very useful not only for the analysis of dynamic behaviors, but also for the performance evaluation of the chassis controllers. The track tension is closely related to the maneuverability of tracked vehicles and the durability of tracks and suspension systems. In order to minimize the excessive load on the tracks and to prevent the peal-off of tracks from the sprocket, the track tension needs to be maintained at the optimum level throughout the maneuver. In this paper, a co-simulation tool is developed such that the performance of the track tension control system can be investigated for various maneuvering tasks. The MBD (multi-body dynamics) vehicle model for tracked vehicles is very complicated (189 bodies, 36 revolute joints, 152 bushing elements and 954 degrees of freedom) and cannot be easily implemented in commercial software. Besides, the track tension controller based on fuzzy logic can be easily constructed in the commercial control software. Therefore, co-simulation methodology is proposed so that the designed tension controller is interfaced into the MBD simulation software. The performance of the tension control system is verified through the proposed co-simulation tool.