The invention relates to a molecular sieve basket structure for a gas chamber of a gas insulated switchgear. The molecular sieve basket structure comprises a molecular sieve basket and a prepressing plate, wherein the prepressing plate is matched with the molecular sieve basket in a clamping manner that the relative movement of the prepressing plate and the sieve basket in the radial direction and the axial direction is limited. The molecular sieve can be detached from the prepressing plate through the clamping matching of the prepressing plate and the molecular sieve basket; the prepressing plate is detached during cleaning or filling, so that the molecular sieve basket is convenient to clean, the labor intensity for cleaning components is reduced, moreover, the absorbent filling efficiency is high, and the problems that foreign matters in the closed space are difficult to clean, the filling efficiency is low and the molecular sieve basket is easy to rust caused by the grinding of a welding seam after a closed space is formed by welding the prepressing plate and the molecular sieve basket are solved; compared with the structure that the prepressing plate and the molecular sieve basket are fixed by bolts, the assembling time of the clamping matching time is shorter, and the assembling efficiency is higher.