As the demand of motion capture in long time and unlimited environment grows, smart wearable devices have become a popular technology in motion capture. These devices are designed to track and analyze human movement with increasing accuracy, while ensures the comfort of wearing and removes the restrictions of the environment. They are expected to continuously monitor, collect, and process motion data and enhancing applications in sports, healthcare, and entertainment. This paper begins with a comprehensive overview of motion capture techniques and the evolution of wearable devices in this domain. We then classify the types of wearables for motion capture and examine the key sensors utilized. Following this, we introduce the algorithms that facilitate the predication of human motion, and discuss the limitations and challenges of current systems. Finally, we explore future trends in wearable motion capture technology and innovations that promise to enhance user experience and broaden the applications of these devices.