The invention discloses a jacking system for buildings, which comprises at least one main jack, at least two first cushion blocks and a plurality of second cushion blocks. The main jack and first cushion blocks are all arranged on a base at the bottom of a building, one first cushion block is respectively arranged on two sides of the main jack, the lengths of the first cushion blocks are adjustable, the plurality of second cushion blocks are fixed between the main jack and the building and between the first cushion blocks and the building. The jacking system uses the main jack and the first cushion blocks for bearing the weight of the building in exchanging mode. The second cushion blocks are positioned between the building and the main jack or the first cushion blocks, and therefore safety of the jacking system for the buildings is guaranteed. The jacking system for the buildings is high in safety, short in construction period and low in cost.