This invention relates to a pneumatic umbrella especially one of which the plunger in the middle section of the barrel will force the air to flow from the lower chamber to the upper chamber through the throttle valve and cause the piston in the upper section to push the sliding hub up to unfold the umbrella when the lower section is pushed up by the hand. When the operating button is depressed, the plunge will be pulled down by the spring and the piston will be sucked down with the sliding hub to fold the umbrella. When the knob set in the bottom cap is turned to some degree and the air release button at the bottom of the knob is depressed, the barrel can be collapsed one section inside another for easy carrying.