Airborne viral and microbial contamination poses a significant challenge in public health, as these pathogens can spread through the air to cause various respiratory diseases, threatening human health. Particularly respiratory-related infectious diseases such as influenza, severe acute respiratory syndrome (SARS), and the novel coronavirus disease (COVID-19) outbreak in late 2019 primarily spread through airborne transmission routes like droplets and aerosols, posing severe threats to human health. Therefore, developing effective indoor air disinfection technologies to reduce pathogen transmission in indoor environments is crucial for controlling and preventing infectious disease outbreaks. Traditional air disinfection methods, such as ultraviolet irradiation, and chemical disinfectant spraying, can reduce microbial counts in the air to some extent but have inherent shortcomings. A novel energy-efficient high-temperature air disinfector is designed in this paper. The core design principle involves rapidly inactivating pathogens using high-temperature air. Through innovative structural design and numerical simulation optimization, the device improves energy utilization efficiency, extends disinfection duration, and reduces energy consumption. Numerical simulation of fluid flow and heat transfer is conducted by computational fluid dynamics (CFD) model. It provides an in-depth analysis of the fluid dynamics and heat transfer characteristics within the sterilizer, offering scientific basis for its design and optimization. A composite structure combining internal baffles and external fins effectively improves energy utilization efficiency and extends disinfection duration. Experimental measurements using the prototype device indicate a heat recovery efficiency exceeding 50 % compared to non-heat-recovery devices. Numerical simulation techniques optimize the internal flow and temperature fields, enabling precise control over disinfection efficacy and energy consumption. An adjustable cooling unit was designed to rapidly reduce post-disinfection high-temperature air to safe discharge standards, enhancing system practicality and safety. The development of this novel energy-efficient high-temperature air disinfector offers a new technological approach for indoor air quality control and infectious disease prevention.