A method for selecting a target network side device, in a wireless communication system, the method comprising: receiving, at a user equipment, from a second network side device a measurement configuration that carries a second preset condition; performing a measurement at the user equipment; sending a measurement report, from the user equipment to the second network side device, reporting that at least one first network side device meets the second preset condition, wherein the measurement report enables the second network side device to make a hand over decision and send a hand over message to the at least one first network side device, wherein the at least one first network side device is a candidate target network side device that is for communication with the user equipment and is configured to perform admission control to allow the user equipment to connect to the at least one first network side device; after the at least one first network side device completes admission control and receives a data packet for the user equipment, from a service gateway, performing a further measurement at the user equipment on receipt of configuration information of the at least one first network side device; selecting, by the user equipment from the at least one first network side device according to the configuration information of the at least one first network side device, a first network side device that meets a first preset condition as a target network side device to communication with the user equipment; and sending, by the user equipment to the first network side device, a message instructing the first network side device to provide a service for the user equipment, so that the first network side device sends the data packet to the user equipment; wherein the data packet for the user equipment is sent by the service gateway to both the at least one first network side device and the second network side device, wherein the first network side device is a target access node and the second network side device is a source access node. receiving, at a user equipment, from a second network side device a measurement configuration that carries a second preset condition; performing a measurement at the user equipment; sending a measurement report, from the user equipment to the second network side device, reporting that at least one first network side device meets the second preset condition, wherein the measurement report enables the second network side device to make a hand over decision and send a hand over message to the at least one first network side device, wherein the at least one first network side device is a candidate target network side device that is for communication with the user equipment and is configured to perform admission control to allow the user equipment to connect to the at least one first network side device; after the at least one first network side device completes admission control and receives a data packet for the user equipment, from a service gateway, performing a further measurement at the user equipment on receipt of configuration information of the at least one first network side device; selecting, by the user equipment from the at least one first network side device according to the configuration information of the at least one first network side device, a first network side device that meets a first preset condition as a target network side device to communication with the user equipment; and sending, by the user equipment to the first network side device, a message instructing the first network side device to provide a service for the user equipment, so that the first network side device sends the data packet to the user equipment; wherein the data packet for the user equipment is sent by the service gateway to both the at least one first network side device and the second network side device, wherein the first network side device is a target access node and the second network side device is a source access node.