The disclosure discloses a method for selecting a temporary core network, a base station and a trunking communication system, which solve the technical problem of selecting a temporary core network when a core network fails. In the disclosure, judgment information is transmitted between base stations in real time, and when a core network fails, according to the judgment information and a predetermined judgement rule, a base station is judged as a temporary core network which substitutes for functions of a core network to serve users of each base station, so that the problem of selecting a temporary core network when a core network fails is solved.