A resource allocation method is provided, which includes: determining a resource block allocation field in downlink control information, where in response to a value indicated by five least significant bits of the resource block allocation field is greater than 20, the resource block allocation field indicates a quantity of resource block groups allocated to a terminal device and an index of a starting resource block group allocated to the terminal device. The method can be applied to the Internet of Things, such as MTC, IoT, LTE-M, M2M, etc.