AI-ROSE is an innovative immunofluorescence staining combined with artificial intelligence image analysis technology that uses a fully automated fluorescence microscope to image pathogens in real time. AI algorithms automatically identify pathogen types (such as bacteria, fungi, etc.) and cellular backgrounds, quickly interpret results, and automatically issue color graphic reports for clinical doctors to take earlier and more accurate targeted treatment for critically ill patients. This study used bronchoalveolar lavage fluid as a biological sample and compared it with traditional examination methods to analyze the diagnostic accuracy and clinical practicality of AI-ROSE in patients with severe pneumonia.