Embodiments of the present invention disclose a resource allocation method, a first node, and a second node. The method includes the following steps: A first node receives downlink control information (DCI) from a second node, where the DCI includes resource indication information, and the resource indication information is used to indicate a transmission resource allocation manner; the first node determines a first resource allocation manner based on the resource indication information, where the first resource allocation manner is used to allocate a transmission resource greater than one narrowband; the first node determines an allocated transmission resource based on the first resource allocation manner and the resource indication information; and the first node transmits data by using the allocated transmission resource.