Adjustable pressure switch, including the base, there are an inhalant canal and two exhalant canals on the base, inhalant canal with the sealed pad is all installed to the exhalant canal intercommunication on the upper wall of every exhalant canal, the sealed pad compresses tightly on the base through the upper cover, fix two upper covers on the base through the bottom plate, there is hollow shellabove the bottom plate, the bottom plate with the shell forms an airtight space, the ejector pin is installed to the sealed face of stacking up, the outside cover of ejector pin has the spring, uppercover and adjusting nut threaded connection, adjusting nut is located the upper portion of spring, at two positive middle scaled supports in position in adjusting nut top, install micro -gap switch on the scale support. Can realize the water level of different pressure through adjusting nut's position and report to the police, the pressure of settlement is reached when pressure and after, the switch.