This study aims to detect pathogens in bronchoalveolar lavage fluid (BALF) from SCAP patients using both metagenomics extended-spectrum pathogenic microorganism sequencing (i.e., a specific version of mNGS) and traditional bacteria culture methods, and to evaluate the effectiveness of mNGS. We also aim to identify risk factors for recovery in SCAP patients. In summary, this study is of great importance in assisting clinicians to formulate an accurate and timely treatment plan for SCAP patients