A water stop structure is mounted to a water jar. A main body includes a depression bar device, a resiliency device, and a water stop member. The depression bar device includes a movable depression bar that is releasably connectable to a hanger formed on the main body. The resiliency device includes a rod that maintains the depression bar in position with a first resilient element. A second resilient element maintains the rod in position to have the water stop member blocking a water passage of the main body. When the depression bar is depressed to travel through a first stroke, the depression bar disengages from the hanger to form an opening therebetween for easy hanging and use of the water jar. When the depression bar travels through a second stroke, the rod drives the water stop member away from the water passage to allow a user to drink water.