Due to fast development of computers and operating systems, HCI (human-computer interface) nowadays has been applied to various fields. This thesis investigates whether the force feedback joystick is suitable to serve as the input device under dynamic environments. We perform a series of experiments and find that there is a linear relationship between the movement time and index difficulty, indicating that force-reflection joystick is a suitable input device for HCI. In addition, reducing movement time and error rate is an important issue for HCI. To deal with that, we thus propose three force-assistant systems including active force, passive force and reminding force. The experimental results show that these three force-assistant systems make improvement on the movement time and error rate. With this study, the user can manipulate the force-reflection joystick with the help of force-assistant systems to accomplish the task more rapidly and accurately.