The invention discloses a resource allocation method and device, which are used for solving the problem that an RRC IDLE-state terminal or an RRC INACTIVE-state terminal in an NR system cannot acquiretransmission resources of a direct communication link. According to the invention, when a direct communication link of a terminal has a data sending requirement; whether direct communication link transmission resources exist or not can be judged; when it is determined that there is no direct communication link sending resource; the terminal initiates an RRC connection management related process or a system information request process to obtain a direct communication link sending resource; therefore, data transmission can be performed on the acquired direct communication link transmission resources, and a specific scheme for acquiring the direct communication link transmission resources to realize direct communication link data transmission when the terminal has a data transmission requirement but has no available direct communication link transmission resources in the NR system is provided.