Abstract: A quick connector includes a body and a tube constrictor. The body has a center through hole for liquid to flow through, and a constrictor groove formed in the center through hole and an O-shaped ring fitted in the constrictor groove. The constrictor groove has an innermost wall, an intermediate straight wall and an outer-sloped wall orderly arranged. The tube constrictor is made integral, having a plurality of elastic petals spaced apart with gaps and each petal has a clamp member formed on an inner wall of its inner end for tightly pushing against the outer surface of a tube inserted in the center hole of the tube constrictor and a pointed tip formed at a lower end of each petal. Then the tube constrictor may loosen the tube to be pulled out and inserted in.