The invention discloses a method for synchronizing an ultra-high-definition video played jointly by multiple terminals. An ultra-high-definition video source is divided into different sub videos through a video cutting technology, and each terminal is in charge of playing a corresponding video and synchronization is performed; and the synchronization includes initialization synchronization and playing synchronization, wherein the initialization synchronization is used for ensuring that all the sub videos start to be played at the same time, and playing synchronization is used for ensuring that the videos are played synchronously in a playing process. The method performs physical division on the ultra-high-definition video, some part of sub videos are played on different terminals, and synchronization processing are performed on the videos, thereby ensuring consistency of video presentation, lowering requirements of video playing for terminal performance, and ensuring synchronization of the same ultra-high-definition video source played by multiple terminals.