The invention relates to a tripod supporting base capable of being rapidly adjusted. The tripod supporting base comprises a base body, an arc pressing plate, an ejector rod, an ejector rod sleeve, a nut and a supporting foot opening and closing mechanism; the arc pressing plate is a uniformly distributed trilobal pressing plate, and the base body is composed of a cover body and a base; the ejector rod sleeve is inserted into a through hole in the top end of the cover body and fixed to the cover body through the nut, the arc pressing plate is arranged in the cover body in a mode of enabling the arcs of the arc pressing plate to face downwards, and the ejector rod is inserted into a blind hole in the arc pressing plate through the ejector rod sleeve; a hinge pin hole in the end of each supporting foot of the supporting foot opening and closing mechanism is connected with a hinge pin hole of the cover body through a hinge pin, the hole center of the hinge pin hole in the end of each supporting foot and the arc-shaped center of the arc pressing plate coincide, and a rolling wheel at the end of each crank arm makes contact with the corresponding arc of the arc pressing plate. The tripod supporting base capable of being rapidly adjusted has the following advantages that by means of the arcs of the arc pressing plates and arrangement of the supporting foot opening and closing mechanism, the three-supporting-foot synchronous action problem which is in suspense for many years is smoothly solved. Not only can the opening degree of the three supporting feet be adjusted, but also two actions of adjusting the length of the supporting feet and the opening degree of the supporting feet can be simultaneously completed in an instant.