There are many people around the world who cannot raise their arms by themselves due to the diseases or accidents, even though they can control their fingers. It will make the patients lose the function of activities of daily living (ADL) of upper-limb. In our previous research, an upper-limb assistance device had been proposed, which can be controlled by several control interfaces. However, those control interfaces require the users to operate by the other hand. According to the object position, the upper-limb motions do not have a certain trajectory. In this article, we focused on developing a Kinect-based upper-limb assistance device. We proposed the motion detection system based on Microsoft Kinect 2 to detect the human motion, and further control the device and assist the user's upper limb. Based on the human intention, the assistive motions can be realized without preprogrammed trajectories. The motions of the device and user were confirmed by the simulation and experiment. By using the system, the users may overcome several motions in ADL without the preprogrammed trajectories.