The invention discloses a wireless sensor network synchronization method based on a dynamic path and a variable period. The method comprises steps of clustering, synchronizing cluster head nodes, synchronizing nodes in a cluster, expanding a network and so on. Hop count maximum of nodes is lowered overall by using a topological structure of clusters, so as to improve node accuracy; when multiple hops exist between clusters, a neighbor cluster head node with small hop count and stable clock frequency is used as a reference node by using a dynamic path mechanism, so that synchronization errors are prevented from accumulating; in the intra-cluster synchronization stage, the protocol adopts a variable period mechanism, thereby eliminating the impact of clock frequency change on synchronizationaccuracy, and saving energy while guaranteeing accuracy. Waiting time for reference node selection, network allowable maximum synchronization error value, and synchronization period limit value can be adjusted according to requirements on synchronization accuracy, energy consumption and convergence in actual application, so as to meet demands in different application scenes.