Instability of the perovskite materials, especially in high humidity, is one of the major limitations that hinders the development of perovskite devices. Herein, to eliminate the degradation of perovskite solar cells in humid air, a water-resistant perovskite absorption layer is proposed by introducing a macrocycle-type cyclodextrin material (β-CD) into the films. The β-CD was proved to be capable of facilitating the crystallization of grains and enhancing the stability of the perovskite by forming supramolecular interactions with organic cations through the hydrogen bonding in the perovskite films. Consequently, the average efficiency of the PSCs remarkably increased from 16.19% to 19.98%. The champion solar cell even delivered an efficiency of 20.09%. The PSCs with β-CD exhibited superior long-term stability in ambient air without encapsulation, which retained 90% of the initial efficiency after continuous AM 1.5 illumination in ambient air with 80% humidity for 300 h.