One case of early diagnosis of pulmonary cryptococcosis by detecting cryptococcal capsular polysaccharide antigen in bronchoalveolar lavage fluid (BALF) with lateral flow immunochromatographic assay(LFA) was reported, so as to provide reference for the diagnosis of pulmonary cryptococcosis. This patient only had Cryptococcus pulmonary infection, LFA was negative for detection of serum capsular polysaccharide antigen on admission, but positive for detection of BALF capsular polysaccharide antigen. Compared with serum, the detectable capsular polysaccharide antigen in BALF appeared positive earlier. Therefore, LFA detection of BALF capsular polysaccharide antigen is more significant for the early diagnosis of pulmonary cryptococcosis.