An access barring method and apparatus and a communication system. The method includes: performing access barring check or access class determination by UE by using parameters defined for a new radio system. The parameters are applicable to all radio resource control (RRC) states. For different public land mobile networks (PLMNs) and/or network slicing, the parameters are identical or different. With the embodiments of this disclosure, selectable parameters are provided for a uniform access control mechanism defined by an NR system, thereby simplifying an access mechanism, and ensuring all-directional compatibility of a terminal state.