Disclosed are a buffer space allocation method and a device. The solution of the present invention enables the division of the buffer space in the buffer resource of a terminal equipment according to the currently configured carrier aggregation mode of the terminal equipment, so that the number of buffer spaces in the buffer can be adjusted according to the number of aggregated carriers, thereby improving the utilization rate of the buffer resource. The method is simple, easy to implement, and applicable to both FDD and TDD systems.