A method for acquiring an Internet Protocol (IP) address is provided that pertains to the communications field. The method includes detecting Packet Data Protocol (PDP) connection information between a mobile broadband device and a network side; acquiring identification information if it is detected that the PDP connection information between the mobile broadband device and the network side changes, where the identification information is used to identify the PDP connection information between the mobile broadband device and the network side; and sending the identification information to a host, so that the host acquires an IP address of the host according to the identification information. In the present invention, the mobile broadband device sends the identification information to the host, so that the host sets, according to the identification information, a value of a state identifier included in the host.