Indoor cat allergens, particularly the major allergen Fel d 1 protein, represent significant environmental triggers for allergic rhinitis, asthma, and other immune-related disorders in humans. With the continuous global increase in pet ownership, cat allergen proteins are prevalent in diverse settings and can even be transmitted to pet-free locations via clothing and animal fur, thereby posing health risks to sensitized individuals. This review systematically provides the molecular characteristics, distribution patterns, and mechanisms of human sensitization to indoor cat allergen proteins. It focuses on a comparative analyses of the principles, sensitivity, and application of commonly used immunological methods (such as various modified ELISA, immunoblotting, and high-throughput multiplex detection technologies) alongside emerging real-time sensing platforms (including QCM, SAW, and LIF). Furthermore, this review summarizes key factors affecting indoor allergen concentrations, such as cat characteristics, architectural environments, human activities, and spatiotemporal variations. It also evaluates the efficacy and limitations of current allergy control strategies, covering source control (e.g., gene editing, immunomodulation), environmental management (e.g., air filtration), and medical treatments (e.g., allergen immunotherapy), and discusses future prospects. This review aims to offer a scientific foundation and systematic references for the detection, control, and public health protection related to indoor allergens.