The present invention relates to a wireless communication system, and more specifically, to a method and an apparatus for enhanced control channel-based operation. A method for a base station for transmitting a downlink control channel in a wireless communication system according to one embodiment of the present invention comprises the steps of: determining one antenna port to be used for the downlink control channel; mapping the downlink control channel to a resource element on the basis of a reference signal for the one antenna port; and transmitting the mapped downlink control channel to a terminal, wherein an index for the one antenna port can be determined on the basis of a control channel element (CCE) index of the downlink control channel derived from the terminal identifier.