The embodiment of the application provides a time sequence management method, a device and a system, wherein the system comprises a control node, an intermediate node and at least one terminal communicated with the intermediate node, the control node and the intermediate node are positioned in a first clock synchronization area, the intermediate node and the at least one terminal are positioned in a second clock synchronization area, and the method comprises the following steps: the intermediate node receives task information from the control node, wherein the task information comprises at least one of starting information and ending information of at least one task; the intermediate node determines operation information of the terminal according to the task information and local clock information, wherein the operation information comprises time for the terminal to execute at least one operation, and the local clock information comprises clock information maintained by the intermediate node; and the intermediate node sends the operation information to the terminal. The clock synchronization method and the clock synchronization device can improve the clock synchronization precision between the terminals.