A method for establishing an optical bypass, applied to a core network architecture established by a network architecture combining an optical transmission device and a routing device, and the core network architecture comprising an optical transmission layer and a routing transmission layer, characterized by, the method comprising: determining, by a routing controller, a link in a target label switched path, LSP, for which an optical bypass needs to be established and the required bandwidth based on bandwidth occupation of each link in the target LSP; determining, by the routing controller, the ingress node and the egress node of the link; sending, by the routing controller, an optical bypass establishment request to an optical transmission controller, wherein the optical bypass establishment request carries information about the ingress node, the egress node and the required bandwidth, and wherein the ingress node and the egress node are routing devices; and when an establishment success notification sent by the optical transmission controller is received, setting, by the routing controller, a second stream forward entry corresponding to the optical bypass for the ingress node and the egress node, and sending, by the routing controller, the set second stream forward entry to the ingress node and the egress node, wherein the establishment success notification is configured to indicate that the optical transmission controller has allocated the optical bypass based on the optical bypass establishment request carrying the information about the ingress node, the egress node and the required bandwidth, set a first stream forward entry corresponding to the optical bypass for each optical transmission device in the optical bypass, and send the set first stream forward entry to the corresponding optical transmission device. determining, by a routing controller, a link in a target label switched path, LSP, for which an optical bypass needs to be established and the required bandwidth based on bandwidth occupation of each link in the target LSP; determining, by the routing controller, the ingress node and the egress node of the link; sending, by the routing controller, an optical bypass establishment request to an optical transmission controller, wherein the optical bypass establishment request carries information about the ingress node, the egress node and the required bandwidth, and wherein the ingress node and the egress node are routing devices; and when an establishment success notification sent by the optical transmission controller is received, setting, by the routing controller, a second stream forward entry corresponding to the optical bypass for the ingress node and the egress node, and sending, by the routing controller, the set second stream forward entry to the ingress node and the egress node, wherein the establishment success notification is configured to indicate that the optical transmission controller has allocated the optical bypass based on the optical bypass establishment request carrying the information about the ingress node, the egress node and the required bandwidth, set a first stream forward entry corresponding to the optical bypass for each optical transmission device in the optical bypass, and send the set first stream forward entry to the corresponding optical transmission device.