The utility model provides an upper decorative plate structure with a side air curtain for an automobile post A, which belongs to the technical field of an automobile and is used for solving the matching problem of the side air curtain. The upper decorative plate structure adopts the following technical scheme: an upper decorative plate has a thickness changing structure, a weakening part corresponding to a spreading space of the side air curtain is arranged at the front part of the upper decorative plate, and the thickness b of the weakening part is smaller than the thickness B of other parts of the upper decorative plate. The upper decorative plate structure breaks through the mode that the conventional upper decorative plate with a fixed thickness realizes the spreading of the side air curtain through secondary disconnection, so that the production technique of the upper decorative plate can be simplified, strict requirements for materials are lowered, the appearance assembling effect of the upper decorative plate cannot be affected and the production cost is reduced; moreover, the falling risk of the upper decorative plate for the post A is eliminated at the same time as the spreading of the side air curtain is realized.