An auto bending structure of sunshade comprising an upper section of bending and a lower section of bending movably riveted featuring that: a sliding rod is provided in the pivotally connected upper section of bending and lower section of bending, through holes are provided on the top and bottom of said sliding rod, the through hole on the bottom of said sliding rod is provided with a guide pin, an arc groove for said guide pin to slide on is provided on the scarf joint part of the lower section of bending, linear groves corresponding to said arc groove for said guide pin to slide on are provided on both sides of said groove of the upper section of bending, a sliding sleeve with a through hole on the bottom is provided on the top of said sliding rod, said through hole on the bottom of said sliding sleeve corresponds to the through hole on the top of said sliding rod, correspondingly, the upper section of umbrella stem is provided with a linear groove on the outer wall and is surrounded by a ring, which is connected with the sliding rod and the sliding sleeve with the connecting pin, which slides in the linear groove to make the ring cooperate with the lower nest moving up and down and pulled by the umbrella string; the present invention is advantageous in simpler structure and lower production cost.