A car sunshade framework which includes: a support frame capable of being placed on a car roof, wherein four corners at the front, rear, left and right sides of the support frame, or two corners at the front part of the support frame are provided with projecting positioning posts, each positioning post is provided with several ribs (3a, 3b, 3c) that can rotate around the axial line and fan out to form fan-like surfaces upon rotating towards the outer edge of the support frame, wherein the several ribs include fixed ribs that are fixed relative to the support frame, two or more driven ribs located above the fixed ribs and set over the positioning posts so that they are able to rotate and driving ribs located above the driven ribs, wherein the upper and lower layers of the several ribs (3a, 3b, 3c) are arranged in an overlapping fashion, where the upper and lower ribs (3a, 3b, 3c) can rotate relative to each other to form an included angle and the spaces between ribs are provided with a linkage mechanism used to drive the rotation of adjacent ribs, wherein the several ribs (3a, 3b, 3c) are formed by rotating elements and support rods, wherein the linkage mechanism consists of pairs of connecting posts and connecting slots respectively disposed on the mating surfaces of adjacent rotating elements, wherein the tops of the connecting posts extend into the connecting slots and can rotate within the connecting slots with the rotation of the rotating elements and both ends of the connecting slots are provided with separating surfaces preventing the connecting posts from continuing to rotate in the connecting slots, characterized in that the car sunshade framework further comprises fixed projecting limit posts on the support frame, serving to prevent the rotation of the driving ribs, wherein the limit posts are located on the inner side of the fixed ribs. a support frame capable of being placed on a car roof, wherein four corners at the front, rear, left and right sides of the support frame, or two corners at the front part of the support frame are provided with projecting positioning posts, each positioning post is provided with several ribs (3a, 3b, 3c) that can rotate around the axial line and fan out to form fan-like surfaces upon rotating towards the outer edge of the support frame, wherein the several ribs include fixed ribs that are fixed relative to the support frame, two or more driven ribs located above the fixed ribs and set over the positioning posts so that they are able to rotate and driving ribs located above the driven ribs, wherein the upper and lower layers of the several ribs (3a, 3b, 3c) are arranged in an overlapping fashion, where the upper and lower ribs (3a, 3b, 3c) can rotate relative to each other to form an included angle and the spaces between ribs are provided with a linkage mechanism used to drive the rotation of adjacent ribs, wherein the several ribs (3a, 3b, 3c) are formed by rotating elements and support rods, wherein the linkage mechanism consists of pairs of connecting posts and connecting slots respectively disposed on the mating surfaces of adjacent rotating elements, wherein the tops of the connecting posts extend into the connecting slots and can rotate within the connecting slots with the rotation of the rotating elements and both ends of the connecting slots are provided with separating surfaces preventing the connecting posts from continuing to rotate in the connecting slots, characterized in that the car sunshade framework further comprises fixed projecting limit posts on the support frame, serving to prevent the rotation of the driving ribs, wherein the limit posts are located on the inner side of the fixed ribs.