A method of establishing a bi-directional Label Switched Path (LSP) includes an establishing request and available upstream and downstream label sets are sent from a first node to a terminal node of the LSP node-by-node. If the available upstream or downstream label set obtained by the terminal node or other nodes is null, the LSP can't be established; if the establishing request is sent to the terminal node and the received available upstream and downstream label sets are not null, the terminal node chooses an upstream label and an downstream label. An establishing response and the upstream and downstream labels are sent from the terminal node to the foregoing nodes node-by-node, and each of other nodes except the first node chooses an upstream label and a downstream label to an upstream node according to the upstream and downstream labels provided by the downstream node.
