The utility model relates to a valve detects fixture and has valve detecting system of these fixture, include: cylinder and the baffle that has the exhaust hole, the cylinder includes: cylinder body, the gland that link up by the cavity, the piston that is the tube-shape, the gland sets up the one end at the cavity to the gland has protruding axle, and the holding is in the cavity, the piston, one end slidable ground cover is located outside protruding, and forms first spacing arch on the outer wall of this end, and the cavity that the cylinder body was followed to the other end exposes, is formed with the first pressure head that supports that the external diameter is lighter than the piston internal diameter, the cylinder body internal face forms and the corresponding spacing arch of second of first spacing arch, on gland and first supports the pressure head, have the first air flue and the second air flue that link up to the tubular structure of piston respectively, just the internal diameter of first air flue is greater than the internal diameter of second air flue. It is not only efficient, make the first pressure head that supports of piston compress tightly by the detection valve through pressure differential, still reduced the possibility of gas leakage, improved the precision that detects.