The utility model belongs to the technical field of the check -up of the diaphragm pressure transmitter of water chemical treatment system, concretely relates to device for connecting be used for unfamiliar pressure transmitter check -up, the device include connecting pipe, check -up joint, check -up flange and blind flange, and check -up flange, blind flange are located the both sides of unfamiliar pressure transmitter pressure sensing respectively, and the outside of check -up flange is equipped with the check -up and connects, and the outside that the check -up connects is equipped with the connecting pipe of being connected its and check gauge. The device can realize the check -up to unfamiliar pressure transmitter at industrial field, easy operation, and convenient to use has greatly improved the work efficiency of this type of changer check -up.