<p>Perovskites have emerged as promising semiconductors for solar cells and optoelectronics. Despite rapid advancements in device performance over the past decade, a quantitative investigation into structure-property relationships remains absent. The core of these innovations in fabrication lies in controlling long-range and short-range microstructural disorders in perovskites, yet their systematic impact across multiple spatial scales remains underexplored. In this review, we elaborate on hidden microstructural disorders, including interfacial disorders and intra-crystal disorders, further delving into their formation mechanisms and effects on mechanical reliability and long-term operational stability of perovskites. Unraveling these effects requires a combined approach of theoretical modeling and experimental characterization. Furthermore, we discuss theory-driven engineering strategies to mitigate such microstructural disorders, enabling the predictable processing and fabrication of stable and high-efficiency perovskite solar cells. This review aims to establish a foundational framework for transitioning from microstructure observation to microstructure control, which represents a critical frontier in the advancement of perovskite photovoltaics.</p>