Abstract: An inflation-deflation device for tourniquet comprising: a barrel (11) and a plunger (12) fitting tightly within the barrel (11). A connecting rod (13) is fixed at one end of the plunger (12). The barrel (11) is fixedly connected at its bottom to a short tube (10). The short tube (10) is connected to the interior space of the barrel (11). The connecting rod (13) having a cruciform cross-section structure, a baffle (16) is perpendicularly fixed to the two sides opposite each other from the central axis of the structure. Connected on the barrel (11) is a clasp (15), the clasp (15) is fixedly connected to the barrel (11) and extends into the interior surface of the barrel (11). The inflation-deflation device has a distinctively designed inflation hole connection tip, to prevent confusion with a standard Luer connection of an ordinary liquid syringe, and also has a distinctively designed deflation limit, to control effectively the volume of gas discharged in a single deflation, and to prevent mishandling.