The utility model relates to the technical field of battery replacing platforms, in particular to a multi-unit modularized side battery replacing platform which comprises a multi-unit modularized battery replacing platform body which is composed of a first ramp, a second ramp, a front wheel positioning portion, a rear wheel positioning portion, a battery replacing portion and a control portion, and the first ramp, the second ramp, the front wheel positioning portion, the rear wheel positioning portion and the battery replacing portion are used for vehicles to enter and exit. The defects in the prior art are overcome, under the matching action of the positioning plate and the like, the pull rod is pulled to move upwards, the pull rod moves upwards so as to drive the sliding rod and the positioning plate to move upwards along with the pull rod, at the moment, the second ramp and the front wheel positioning part can be spliced, the connecting plate is moved to the position below the positioning plate, and then the front wheel positioning part is spliced. And then the pull rod is loosened, so that the positioning plate is pushed to move downwards and is positioned and mounted with the connecting plate under the automatic reset action of the telescopic spring, splicing mounting can be quickly completed, the splicing device is convenient to disassemble and replace in the later period, the splicing device is simple and convenient, and the difficulty of mounting operation is further reduced.