A method and a device for determining a search space and for determining candidate control channel resources are provided in present invention. The method for determining the search space includes: determining the number of downlink control information bits of each type of control channel currently required to be monitored by a UE; determining a temporary search space corresponding to the each type of control channel according to a mapping relationship currently used by the UE; and determining that an actual search space corresponding to a selected type of control channel is all or a part of CCEs of a union of temporary search spaces corresponding to all or a part of control channels with the same number of the downlink control information bits, when the DCI bit number of one or more other control channels is the same as the DCI bit number of the selected type of control channel.