The present application relates to the field of communications, and disclosed are a method and device for determining an information domain value in a DCI. The method and device are used for reducing HARQ feedback overheads, and the method comprises during HARQ feedback, determining a value set indicated by a timing relationship in a fallback DCI (equivalent to a format 1_0 of a DCI) according to a value set indicated by a timing relationship in a non-fallback DCI (equivalent to a format 1-1 of a DCI), to overcome the problem of increasing a codebook caused by different value ranges indicated by the timing relationships in the fallback DCI and in the non-fallback DCI, so that the HARQ feedback overheads are effectively reduced, thus the system running load is reduced, and the system performance is effectively ensured.