Bronchoalveolar lavage fluid (BALF) is rich in various bioactive substances such as cytokines and enzymes, making it a high-quality clinical specimen and research sample. It holds significant value in fields such as etiological analysis, proteomics, pathology, and disease diagnosis and treatment. This article systematically reviews the key technical points for the preservation of BALF samples and provides an in-depth interpretation of bronchoalveolar lavage fluid from an application perspective. The aim is to offer references for the standardization of sample preservation practices and to promote the widespread use of BALF samples in clinical research.