Provided is a distributed antenna system (DAS) for multi-frequency band and multi-carrier equipped with an open radio access network (O-RAN) remote unit (RU) according to an O-RAN technology standard for building a next-generation radio infrastructure. To this end, the DAS for multi-carrier and multi-frequency band based on an O-RAN standard includes an O-RAN RU connected to a fronthaul network according to an O-RAN split option specification of base station transceiver systems (BTSs), and including a plurality of O-RAN RUs to accommodate a plurality of carriers and a plurality of frequency bands; and a channel combiner to which outputs of the plurality of O-RAN RUs are combined.