The invention relates to a method, a device and a system for scheduling resources of the narrowband Internet of Things. The method includes the following steps of detecting whether or not data in a downlink buffer meets a preset resource scheduling trigger condition, and if yes, calculating a virtual BSR corresponding to a to-be-scheduled device according to a current communication event of the to-be-scheduled device, wherein the virtual BSR is used for indicating the size of the scheduled resources of the to-be-scheduled device; when the preset scheduling delay duration is reached, schedulinguplink resources for the to-be-scheduled device according to the virtual BSR, and sending downlink control information, generated according to the virtual BSR, to the to-be-scheduled device. The method, the device and the system have the advantages that idle resource consumption in the random access process can be reduced, and the resource scheduling efficiency is improved.