An umbrella has a column, an upper nest, a movable lower nest, a plurality of long rods, a plurality of short rods. The upper nest has a plurality of first slots spaced apart on a periphery of the upper nest, a plurality of first pins is disposed on the upper nest respectively; each long rod has a first rod-hanging hook on the top end thereof, each first rod-hanging hook hooks on the corresponding first pin; the lower nest has a plurality of second slots spaced apart on a periphery of the lower nest, a plurality of second pins are disposed on the lower nest respectively; each short rod has a second rod-hanging hook on the bottom end thereof, each second rod-hanging hook hooks on the corresponding second pin. The structure of the present invention is simple and reasonable, the machining is convenient and the cost is low.