The invention discloses a divide and forward multicast (DFM) strategy-based long-life adjustment method for multicast trees. The method comprises the following steps of: sorting shared nodes according to the occupied number of the multicast trees, and separating the sorted shared nodes from participation multicast trees one by one; selecting the participation multicast trees according to the number of sub nodes in the process of separating the shared nodes; and seeking standby father nodes in the selected participation multicast trees for the sub nodes of the shared nodes, and receiving and sending messages to execute a DFM strategy. By the method, the shared nodes can be separated by using the DFM strategy under the condition that the shared nodes still can exist after a plurality of multicast trees are established, so that the shared nodes can be converted into ordinary nodes which are only positioned in one multicast tree as many as possible, the work time of a wireless sensor networks is prolonged, long-life multicast data transmission is maintained, and energy consumption among the nodes is balanced.