Abstract:A flexible multicast Spanning Tree Algorithm based on wireless sensor network was proposed, which called MSTA(Multicasting Spanning Tree Algorithm ). MSTA constructed an overlay multicast tree in a dynamic, decentralized and incremental way. It not only can satisfy the performance goals and the needs of a wide range of applications. But also it is highly adaptive: it reconfigures the tree in response to mobility or congestion. In addition, MSTA has advantages of an application layer protocol of simplicity of deployment and independence from lower layer protocols. Compared with ODMRP , MSTA performs significantly.