The embodiments of the present invention relate to the technical field of wireless communications, and particularly, to a time-division duplexing communication method, system and device, which are used for solving the problem in the prior art that there is no uplink or downlink HARQ sequential relationship for a dynamic uplink and downlink subframe distribution solution. A time-division duplexing uplink data sending method in the embodiments of the present invention comprises: through a subframe n in a wireless frame, user equipment receiving indication information which comes from the network side; and according to the indication information, when it is determined that PUSCH data is required to be sent to the network side, sending the PUSCH data through at least one uplink subframe after the subframe n, the subframe n being a downlink fixed subframe or a special subframe. Proposed is an uplink and downlink HARQ sequential relationship for a dynamic uplink and downlink subframe distribution solution, so that a dynamic TDD system can transmit uplink and downlink data.