A method for realizing interaction of optical channel data unit (ODUk) protection tangent rings are provided. A node used for protection of the ODUk and a receiving unit, a sending unit, a protected receiving unit and a protected sending unit on the node are selected. A connection between a receiving service unit and the protected sending unit with the same transmission direction on the node is established, or a connection between a sending service unit and the protected receiving unit with the same transmission direction on the node is established. Two virtual nodes are established on the node if the node is an intersection node, and connections between the receiving service unit and the protected sending unit, and between the sending service unit and the protected receiving unit are established respectively in each direction of both directions through one of the virtual nodes.