An information transmission method, comprising: determining, by user equipment, UE (10, 110), when the UE (10, 110) is in an idle state, whether there is to-be-transmitted uplink information; sending (320, 201), by the UE (10, 110), a first request message to a first access network device (20, 120) when the UE (10, 110) determines that there is to-be-transmitted uplink information, wherein the first request message is a first air interface message for the UE (10, 110) to switch from the idle state to a connected state, and the first request message carries uplink non-access stratum, NAS, information and air interface identity information that is stored on the UE (10, 110), wherein the uplink NAS information comprises an attach request message; and storing, by the UE (10, 110), before the UE (10, 110) determines whether there is to-be-transmitted uplink information, air interface identity information that is pre-allocated by the first access network device (20, 120) to the UE (10, 110) before the UE (10, 110) performs an attach process, wherein the air interface identity information corresponds to at least one UE (10, 110) that communicates with the first access network device (20, 120); receiving, by the UE (10, 110), a response message sent by the first access network device (20, 120), wherein the response message carries attach success indication information and dedicated air interface identity information of the UE (10, 110), and the dedicated air interface identity information is allocated by a core network device (30, 130) or the first access network device (20, 120) to the UE (10, 110); and storing, by the UE (10, 110), the dedicated air interface identity information, and performing information transmission with the first access network device (20, 120) by using the dedicated air interface identity information. determining, by user equipment, UE (10, 110), when the UE (10, 110) is in an idle state, whether there is to-be-transmitted uplink information; sending (320, 201), by the UE (10, 110), a first request message to a first access network device (20, 120) when the UE (10, 110) determines that there is to-be-transmitted uplink information, wherein the first request message is a first air interface message for the UE (10, 110) to switch from the idle state to a connected state, and the first request message carries uplink non-access stratum, NAS, information and air interface identity information that is stored on the UE (10, 110), wherein the uplink NAS information comprises an attach request message; and storing, by the UE (10, 110), before the UE (10, 110) determines whether there is to-be-transmitted uplink information, air interface identity information that is pre-allocated by the first access network device (20, 120) to the UE (10, 110) before the UE (10, 110) performs an attach process, wherein the air interface identity information corresponds to at least one UE (10, 110) that communicates with the first access network device (20, 120); receiving, by the UE (10, 110), a response message sent by the first access network device (20, 120), wherein the response message carries attach success indication information and dedicated air interface identity information of the UE (10, 110), and the dedicated air interface identity information is allocated by a core network device (30, 130) or the first access network device (20, 120) to the UE (10, 110); and storing, by the UE (10, 110), the dedicated air interface identity information, and performing information transmission with the first access network device (20, 120) by using the dedicated air interface identity information.