Embodiments of the present invention relate to the field of security channel multiplexing, and disclose a method and an apparatus for multiplexing a HIP security channel. A method includes: receiving a message for requesting to transmit data; detecting whether a HIP security channel is established with the HIP host; if true, transmitting control signaling to the HIP host, where the control signaling is used to request to multiplex the HIP security channel to transmit data of the traditional host; if a response message returned from the HIP host is received, transmitting the data of the traditional host to the HIP host through the HIP security channel. With embodiments of the present invention, the quantity of HIP security channels established between the HIP proxy and the HIP host and the loads of maintaining the security channel can be reduced, and the utilization of the HIP security channel is increased.