A communication method, wherein the method is applicable to a terminal device or a chip in the terminal device, and the method comprises: receiving indication information from a first access network device, wherein the indication information is used to indicate to fall back a capability of the terminal device to a first protocol version; and communicating, based on the indication information, with the first access network device by using first capability information, wherein a protocol version corresponding to the first capability information is lower than or equal to the first protocol version; wherein the method is characterised in that it further comprises: determining that a network capability area to which the first access network device belongs changes, wherein the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; and sending an RRC connection setup request message to the first access network device; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes; or in that the method further comprises: sending an RRC connection setup request message to a second access network device, wherein a network capability area to which the second access network device belongs is different from a network capability area to which the first access network device belongs, the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes. receiving indication information from a first access network device, wherein the indication information is used to indicate to fall back a capability of the terminal device to a first protocol version; and communicating, based on the indication information, with the first access network device by using first capability information, wherein a protocol version corresponding to the first capability information is lower than or equal to the first protocol version; wherein the method is characterised in that it further comprises: determining that a network capability area to which the first access network device belongs changes, wherein the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; and sending an RRC connection setup request message to the first access network device; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes; or in that the method further comprises: sending an RRC connection setup request message to a second access network device, wherein a network capability area to which the second access network device belongs is different from a network capability area to which the first access network device belongs, the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes. determining that a network capability area to which the first access network device belongs changes, wherein the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; and sending an RRC connection setup request message to the first access network device; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes; or in that the method further comprises: sending an RRC connection setup request message to a second access network device, wherein a network capability area to which the second access network device belongs is different from a network capability area to which the first access network device belongs, the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes. sending an RRC connection setup request message to a second access network device, wherein a network capability area to which the second access network device belongs is different from a network capability area to which the first access network device belongs, the network capability area comprises at least one access network device, and each access network device in the network capability area has the same capability; wherein the RRC connection setup request message comprises a cause value, and the cause value is used to indicate that a network capability area changes.