A method of sending downlink information, comprising: receiving, by an Access and Mobility Management Function, AMF, entity, a first notification message sent by a Network Function, NF, entity and configured to call a first service of the AMF entity; sending to the NF entity, by the AMF entity, indication information; receiving, by the AMF entity, a second notification message sent by the NF entity and configured to call a second service of the AMF entity; and sending, by the AMF entity, downlink information to the UE, characterized in that, the indication information is configured to indicate that a User Equipment, UE, is in a connected state, the first notification message carries indication information configured to indicate that the NF entity is to send the downlink information, the downlink information that the NF entity is to send is a downlink signaling or downlink data, and the downlink signaling is that the NF entity is to send to the UE or the downlink signaling is configured to trigger the AMF entity to send a downlink signaling to the UE, wherein, in the case that the downlink information that the NF entity is to send is the downlink signaling, the second notification message carries the downlink signaling; the sending, by the AMF entity, the downlink information to the UE comprises: sending, by the AMF entity, the downlink signaling to the UE, or the downlink signaling is sent by the AMF entity by triggering; or in the case that the downlink information that the NF entity is to send is the downlink data, the second notification message carries a user plane establishment signaling configured to instruct the AMF to establish a user plane for the downlink data; the sending, by the AMF entity, the downlink information to the UE comprises: establishing, by the AMF entity, a user plane data channel between the NF entity and the LTE, to enable the NF entity to send the downlink data to the LTE through the user plane data channel. receiving, by an Access and Mobility Management Function, AMF, entity, a first notification message sent by a Network Function, NF, entity and configured to call a first service of the AMF entity; sending to the NF entity, by the AMF entity, indication information; receiving, by the AMF entity, a second notification message sent by the NF entity and configured to call a second service of the AMF entity; and sending, by the AMF entity, downlink information to the UE, characterized in that, the indication information is configured to indicate that a User Equipment, UE, is in a connected state, the first notification message carries indication information configured to indicate that the NF entity is to send the downlink information, the downlink information that the NF entity is to send is a downlink signaling or downlink data, and the downlink signaling is that the NF entity is to send to the UE or the downlink signaling is configured to trigger the AMF entity to send a downlink signaling to the UE, wherein, in the case that the downlink information that the NF entity is to send is the downlink signaling, the second notification message carries the downlink signaling; the sending, by the AMF entity, the downlink information to the UE comprises: sending, by the AMF entity, the downlink signaling to the UE, or the downlink signaling is sent by the AMF entity by triggering; or in the case that the downlink information that the NF entity is to send is the downlink data, the second notification message carries a user plane establishment signaling configured to instruct the AMF to establish a user plane for the downlink data; the sending, by the AMF entity, the downlink information to the UE comprises: establishing, by the AMF entity, a user plane data channel between the NF entity and the LTE, to enable the NF entity to send the downlink data to the LTE through the user plane data channel.