Abstract: An improved structure of a quick-connect pipe fitting, and particularly a structure for a quick-connect pipe fitting used to connect a pressure pipe or a hydraulic tubing in a system comprises a compression member on top of a lock washer such that the compression member is fitted and secured in a base. When a pressure pipe is inserted into the pipe fitting, the compression member is screwed on but remains loose. In disconnecting the pressure pipe, the compression member is pushed downward, against the lock washer so as to disengage the inner teeth thereof from the pipe. The pressure pipe is no longer locked and may be pulled out easily. In addition, the quick-connect pipe fitting may include a connecting member which is used to install an air valve. Such air valve comprises a seal ring, a vent valve having vent holes, a connecting base and a spring.