A method for creating an inter-domain bidirectional tunnel, comprising the steps of; receiving, by a domain-boundary node, an inter-domain path creation PCInitiate message sent by a path computation element, PCE, wherein the PCInitiate message comprises mapping path information and bidirectional tunnel instruction information, the mapping path information being for creating an inter-domain label switched path, LSP; obtaining an actual transmission path based on the mapping path information and the bidirectional tunnel instruction information, wherein the actual transmission path is used for data transmission between intra-domain or inter-domain nodes, wherein the method further comprises: determining a type of the domain-boundary node, wherein the type comprises an ingress boundary node, an inter-domain boundary node, and an egress boundary node, wherein the mapping path information for the inter-domain LSP comprises path segment information, and the bidirectional tunnel instruction information comprises an association type of the path segment information, wherein the path segment information comprises intra-domain path segment information and inter-domain path segment information, wherein, in a case where the domain-boundary node is an ingress boundary node or an egress boundary node, the association type is bidirectional LSP association, the step of obtaining the actual transmission path based on the mapping path information and the bidirectional tunnel instruction information comprises the steps of: calculating a corresponding bidirectional-tunnel path segment according to the bidirectional LSP association and an intra-domain path computation rule; and determining the actual transmission path based on the bidirectional-tunnel path segment, and binding the path, and wherein, in a case where the domain-boundary node is an inter-domain boundary node, the association type is stitching LSP association; the intra-domain path segment information is path segment information from the domain-boundary node to a previous intra-domain node, and the inter-domain path segment information is a forwarding path from the domain-boundary node to a domain-boundary node in another domain, the step of obtaining the actual transmission path based on the mapping path information and the bidirectional tunnel instruction information comprises a step of: splicing the intra-domain path segment information and the forwarding path according to the stitching LSP association to generate an inter-domain bidirectional mapped path and an inter-domain bidirectional-tunnel path segment, wherein the stitching LSP association is stored as data in a TLV format in the PCInitiate message and sent along with the PCInitiate message, and the TLV format comprises a Type field, a Length field, and a Reserved field. receiving, by a domain-boundary node, an inter-domain path creation PCInitiate message sent by a path computation element, PCE, wherein the PCInitiate message comprises mapping path information and bidirectional tunnel instruction information, the mapping path information being for creating an inter-domain label switched path, LSP; obtaining an actual transmission path based on the mapping path information and the bidirectional tunnel instruction information, wherein the actual transmission path is used for data transmission between intra-domain or inter-domain nodes, wherein the method further comprises: determining a type of the domain-boundary node, wherein the type comprises an ingress boundary node, an inter-domain boundary node, and an egress boundary node, wherein the mapping path information for the inter-domain LSP comprises path segment information, and the bidirectional tunnel instruction information comprises an association type of the path segment information, wherein the path segment information comprises intra-domain path segment information and inter-domain path segment information, wherein, in a case where the domain-boundary node is an ingress boundary node or an egress boundary node, the association type is bidirectional LSP association, the step of obtaining the actual transmission path based on the mapping path information and the bidirectional tunnel instruction information comprises the steps of: calculating a corresponding bidirectional-tunnel path segment according to the bidirectional LSP association and an intra-domain path computation rule; and determining the actual transmission path based on the bidirectional-tunnel path segment, and binding the path, and wherein, in a case where the domain-boundary node is an inter-domain boundary node, the association type is stitching LSP association; the intra-domain path segment information is path segment information from the domain-boundary node to a previous intra-domain node, and the inter-domain path segment information is a forwarding path from the domain-boundary node to a domain-boundary node in another domain, the step of obtaining the actual transmission path based on the mapping path information and the bidirectional tunnel instruction information comprises a step of: splicing the intra-domain path segment information and the forwarding path according to the stitching LSP association to generate an inter-domain bidirectional mapped path and an inter-domain bidirectional-tunnel path segment, wherein the stitching LSP association is stored as data in a TLV format in the PCInitiate message and sent along with the PCInitiate message, and the TLV format comprises a Type field, a Length field, and a Reserved field.