In a file repair method for a user equipment (UE), the UE receives a target file multicasted by a network side in a file download transmission (FDT) manner. The method includes transmitting, by the UE, a multicast attempt repair request for the target file to the network side in a first time period after determining that the target file needs to be repaired, where the first time period does not exceed a time period of a Back-off time of a current session, receiving, by the UE, a feedback message transmitted by the network side, where the feedback message instructs the UE to perform multicast repair, and performing, by the UE, the multicast repair on the target file in response to the received feedback message.