Abstract: Microplastics are ubiquitous in the atmospheric environment, and inhalation exposure to them poses a potential threat to human health. This paper reviews the internal exposure of microplastics in the human respiratory system through literature retrieval, analyzes the main influencing factors of their presence, and discusses the challenges faced in current presence research. Studies have shown that microplastics are detected in nasal tissues, nasal lavage fluid, sputum, bronchoalveolar lavage fluid, and lung tissues of the respiratory system. Polyethylene terephthalate (PET), polyethylene (PE), polystyrene (PS), and polypropylene (PP) are the main polymer types present in the human respiratory system. Physiological characteristics, personal characteristics, and environmental external exposure may affect the presence of microplastics in the human respiratory system. However, the limitations of existing detection and analysis methods in spatial resolution have led to insufficient understanding of the presence levels of microplastics. Future research should focus on developing highly sensitive analysis techniques for nanoscale plastics, while strengthening the assessment of microplastic exposure in susceptible populations and further exploring the toxic effects and mechanisms of inhalation exposure to microplastics.