In the process of sport learning, learners spend a lot of time on practicing in order to develop correct action habit. Take golf practice as an example. Without the supervising of coaches, novices may keep practicing wrong swing actions, and that will cost more time later on to correct the wrong habit. It would be helpful to let learners can be aware of incorrect swing actions in self-training. In this work, we propose an IMU-based solution to help learners by allowing them to review their swing trajectories and also learn key features of the swings. In the proposed system, an IMU composed of an accelerometer, a magnetometer and a gyroscope is installed on the golf club to collect inertial motion data. From the collected data, swing trajectories can be calculated and swing features can also be extracted.