Embodiments of the present invention relate to communications technologies, and provide a data transmission method and an apparatus. The method includes: sending, by a base station, a grouping instruction to a target terminal, where the grouping instruction is used to group, in a preset grouping manner, terminals in a cell in which the target terminal is located into N groups, totally or partially different resources are allocated to terminals in different groups of the N groups, and a resource corresponding to an ith group of the N groups is used by a terminal in the ith group in uplink non-scheduled transmission; and receiving data that is sent by the target terminal using a target resource. In the solutions, terminals in a cell are grouped, and terminals in a same group contend for a resource allocated to the group. This mitigates resource collision when an uplink non-scheduled transmission solution is used.