This invention discloses a multi-layer virtual private local area network service network, wherein the user side network includes a Userfacing Provider Edge (UPE) and a Customer Edge (CE); the UPE and CE in the user side network are connected by using a tree structure; the nodes on the same level in the tree structure do not communicate with each other; after receiving data from a node on the lower level, the node can only forward the data to a node on the upper level The invention also discloses a data processing method based on the multi-layer virtual private local area network service network, which includes the following steps: after the node in the tree structure receives data, it determines, according to the identification information of the port from which the data is received, whether the data is from a node on the upper level or a node on the lower level; when it is determined that the data is from the node on the lower level, the data is forwarded to a node on the upper level; when it is determined that the data is from the node on the upper level, the data is forwarded according to the destination address of the data; when the destination address of the data can not be determined, the data is broadcasted to all the nodes on the lower level With the invention, it can be supported that multiple UPEs are located in the user side network, and it can be avoided that a network storm is formed in the user side network