In this paper, we introduce walking assist robot systems for the elderly people to manage the independent living over a long period of time in serious aging society. This research especially focuses on the motion control method of the walking assist robot systems based on the human linkage model calculated in real time. According to the human linkage model, the robot systems could calculate a position of the user's center of gravity and the joint moment applied around the each joint of the user in real time. Based on the information of the user, the robot systems could support the walking appropriately. The motion control algorithms based on the human model are implemented to the walker-type walking assist system and the wearable walking assist system experimentally, and experimental results illustrate the validity of the proposed methods.