A method for setting up a first Point to Multi-Point Label Switch Path, P2MP LSP, characterized by comprising: receiving, by a node, a first message from an upstream node, the first message including identification information of a second P2MP LSP, and the first message requesting for setting up the first P2MP LSP, the first P2MP LSP and the second P2MP LSP sharing a label; when the node is a sink node of the first P2MP LSP, assigning, by the sink node, in an upstream link of the node, a first label to the first P2MP LSP if the second P2MP LSP has the first label in the upstream link of the node; assigning, by the sink node, in the upstream link of the node, a second label to the first P2MP LSP if the second P2MP LSP does not have the label in the upstream link of the node; sending, by the sink node, a second message to the upstream node, the second message carrying the label which is assigned to the first P2MP LSP in the upstream link of the node; when the node is an intermediate node of the first P2MP LSP, sending, by the intermediate node, the first message to a downstream node, and receiving, by the intermediate node, a third message from the downstream node, the third message carrying the label which is assigned to the upstream link of the downstream node by the downstream node; assigning, by the intermediate node, in the upstream link of the node, a third label to the first P2MP LSP if the second P2MP LSP has the third label in the upstream link of the node; assigning, by the intermediate node, in the upstream link of the node, a fourth label to the first P2MP LSP if the second P2MP LSP does not have a label in the upstream link of the node; and sending, by the intermediate node, a fourth message to the upstream node, the fourth message carrying the label which is assigned to the first P2MP LSP in the upstream link of the node. receiving, by a node, a first message from an upstream node, the first message including identification information of a second P2MP LSP, and the first message requesting for setting up the first P2MP LSP, the first P2MP LSP and the second P2MP LSP sharing a label; when the node is a sink node of the first P2MP LSP, assigning, by the sink node, in an upstream link of the node, a first label to the first P2MP LSP if the second P2MP LSP has the first label in the upstream link of the node; assigning, by the sink node, in the upstream link of the node, a second label to the first P2MP LSP if the second P2MP LSP does not have the label in the upstream link of the node; sending, by the sink node, a second message to the upstream node, the second message carrying the label which is assigned to the first P2MP LSP in the upstream link of the node; when the node is an intermediate node of the first P2MP LSP, sending, by the intermediate node, the first message to a downstream node, and receiving, by the intermediate node, a third message from the downstream node, the third message carrying the label which is assigned to the upstream link of the downstream node by the downstream node; assigning, by the intermediate node, in the upstream link of the node, a third label to the first P2MP LSP if the second P2MP LSP has the third label in the upstream link of the node; assigning, by the intermediate node, in the upstream link of the node, a fourth label to the first P2MP LSP if the second P2MP LSP does not have a label in the upstream link of the node; and sending, by the intermediate node, a fourth message to the upstream node, the fourth message carrying the label which is assigned to the first P2MP LSP in the upstream link of the node.