Disclosed are a method and a device for processing message overload. The method comprises: a base station receiving a downlink NAS transmission message sent by a network device, the downlink NAS transmission message comprising indication information indicating whether to transmit an SMS; when being congested, the base station determining, according to the indication information, that the received downlink NAS transmission message is used to transmit an SMS; and processing the downlink NAS transmission message used for transmitting an SMS.