The invention provides a determining method of uplink and downlink timing relationship. The determining method of the uplink and downlink timing relationship comprises the following steps that when a plurality of service cells with different uplink and downlink configuration are gathered under a time division duplex system, the uplink and downlink timing relationship of a particular service cell is determined in the following mode: sub-frames of the particular service cell are divided into k kinds, the uplink and downlink timing used by each kind of sub-frame is one kind of the uplink and downlink timings which are predefined, the uplink and downlink timings used by the sub-frame are different, k is larger than one, and the particular service cell is one or more service cells of the gathered service cells. The invention further provides a determining device of the uplink and downlink timing relationship.