A pipe adapter may comprise a main body, an O-ring, a conical ring, an engaging ring, a control unit and a locating, tube, and a front opening formed at a front end of the main body which is configured to receive a pipe. Since the conical ring, engaging ring and locating tube are coupled in sequence instead of covering one by one such that there is no need to enlarge a diameter of the front opening of the main body for receiving the above components thereby lowering the manufacturing cost.
