A communication method, comprising: determining, by a terminal device in a first state, that a paging area of the terminal device is changed, wherein the first state comprises a state in which the terminal device monitors paging and has stored connection context information of the terminal device; sending, by the terminal device, a first message to a first access network device, wherein the first message is used to notify the first access network device that the paging area of the terminal device is changed, and the first access network device is a serving access network device of the terminal device; receiving, by the terminal device, a second message sent by the first access network device based on the first message; determining, by the terminal device based on the second message, a to-be-entered state of the terminal device; and when the terminal device determines that the to-be-entered state is a second state, entering, by the terminal device, the second state based on the stored connection context information, wherein the second state comprises that the terminal device and the first access network device are connected; wherein the sending, by the terminal device, the first message, comprises: sending, by the terminal device, the first message on a first signaling channel of a common channel; and wherein the receiving, by the terminal device, the second message, comprises: activating, by the terminal device based on a signaling channel parameter saved in the connection context information of the terminal device, a second signaling channel of a dedicated channel; and receiving, by the terminal device, the second message on the second signaling channel. determining, by a terminal device in a first state, that a paging area of the terminal device is changed, wherein the first state comprises a state in which the terminal device monitors paging and has stored connection context information of the terminal device; sending, by the terminal device, a first message to a first access network device, wherein the first message is used to notify the first access network device that the paging area of the terminal device is changed, and the first access network device is a serving access network device of the terminal device; receiving, by the terminal device, a second message sent by the first access network device based on the first message; determining, by the terminal device based on the second message, a to-be-entered state of the terminal device; and when the terminal device determines that the to-be-entered state is a second state, entering, by the terminal device, the second state based on the stored connection context information, wherein the second state comprises that the terminal device and the first access network device are connected; wherein the sending, by the terminal device, the first message, comprises: sending, by the terminal device, the first message on a first signaling channel of a common channel; and wherein the receiving, by the terminal device, the second message, comprises: activating, by the terminal device based on a signaling channel parameter saved in the connection context information of the terminal device, a second signaling channel of a dedicated channel; and receiving, by the terminal device, the second message on the second signaling channel. sending, by the terminal device, the first message on a first signaling channel of a common channel; and wherein the receiving, by the terminal device, the second message, comprises: activating, by the terminal device based on a signaling channel parameter saved in the connection context information of the terminal device, a second signaling channel of a dedicated channel; and receiving, by the terminal device, the second message on the second signaling channel. activating, by the terminal device based on a signaling channel parameter saved in the connection context information of the terminal device, a second signaling channel of a dedicated channel; and receiving, by the terminal device, the second message on the second signaling channel.