The invention provides a group service transmission method and apparatus based on a PRACH (physical random access channel). The method comprises the following steps: a base station configures PRACH resources in advance, wherein the PRACH resources comprise N groups of PRACHs and corresponding relations between each PRACH in each PRACH group with a CQI grade; and the base station sends a notification message to group UE in a group so that the group UE can feed NACK information to the base station through the PRACH resources, the base station, when it is detected that the UE feeds the NACK information back, obtains a CQI expected by the UE feeding back the NACK information through a CQI grade corresponding to the PRACH of the detected feedback NACK information, and the base station, according to the obtained CQI expected by at least one piece of UE, performs retransmission scheduling and adjusts the MCS of primary transmission of the next time, wherein the notification message comprises a group RNTI, carried configuration information and the PRACH resources. The group service transmission method and apparatus based on the PRACH, provided by the invention, can improve the accuracy of group service transmission and can also decentralize interference caused to a local cell and adjacent cells.