The invention discloses a memory allocation method and device. The method comprises the steps that information of each slab class is obtained; each slab class influence factor is calculated according to a preset minimum influence factor selection algorithm and the information; the slab class with the minimum influence factor is selected as a source slab class, and the slab with the largest number of exchange amount within a period of time is set as the target slab; one slab memory in the source slab class is cleared up and recycled, and then redistributed to the target slab, a minimum influence factor selection algorithm is provided, the characteristic of storage data under the compression condition are comprehensively considered, and the proper source slab class and the target slab are reasonably selected, recycled and redistributed; a Memcached memory distribution mechanism is adjusted, regions are divided effectively on the basis of the idle, full and other slab storage states, and the idle slab at the tail end is started to be recycled when the memory is needed.