The present disclosure provides a downlink control channel detection method, a downlink control channel transmission method, a network side device and a User Equipment (UE). The downlink control channel detection method includes: determining a detection mode for a downlink control channel; and detecting the downlink control channel in accordance with the determined detection mode for the downlink control channel. The detection mode for the downlink control channel includes a one-stage detection mode in which control information for the detection of a data channel is acquired through a single downlink control channel detection operation and a multiple-stage detection mode in which the control information for the detection of the data channel is acquired through at least two downlink control channel detection operations.