Provided are a method and apparatus for updating time division duplex (TDD) uplink and downlink configuration and a method and apparatus for notifying TDD reconfiguration information. The method for updating TDD uplink and downlink configuration includes: after receiving TDD reconfiguration information sent by a network side, a user equipment (UE) immediately determining a time period of using a TDD uplink and downlink configuration indicated in the received TDD reconfiguration information (S202), and using the TDD uplink and downlink configuration indicated by the received TDD reconfiguration information in the time period; or, after receiving the TDD reconfiguration information sent by the network side, the UE immediately using the TDD uplink and downlink configuration indicated in the received TDD reconfiguration information (S204). By means of the present invention, the problem of service delay and/or resource waste due to a mismatching between the TDD uplink and downlink configuration and current uplink
