The invention provides a peritoneum dialysis liquid exchange auxiliary device and relates to the technical field of peritoneum dialysis. The structure of the peritoneum dialysis liquid exchange auxiliary device comprises a first guide rail and a second guide rail, wherein the first guide rail is provided with a first bracket and a second bracket which can slide along the first guide rail; a third bracket, which can slide along the second guide rail, is arranged on the second guide rail; in a liquid exchange process, when a dialysis liquid connector is in butt joint with a peritoneum dialysis short pipe, the dialysis liquid connector is clamped on the first bracket, and the peritoneum dialysis short pipe is clamped on the second bracket; by pushing the first bracket and the third bracket, the dialysis liquid connector and the peritoneum dialysis short pipe, which are accurately aligned, are connected; after liquid is exchanged, the dialysis liquid connector is separated from the peritoneum dialysis short pipe, and an iodophor cap is clamped on the second bracket; by pushing the second bracket and the third bracket, the iodophor cap is aligned to a pipe opening of the peritoneum dialysis short pipe and covers the pipe opening. In a whole liquid exchange process, the auxiliary device can be used for effectively preventing touch pollution and particularly can realize accurate alignment for patients with amblyopia or patients with hand tremor; the convenience for liquid exchange operation is greatly improved.