Objective To explore the clinical significance of CT-guided percutaneous lung biopsy (CT-GPLB) in the diagnosis of pulmonary infectious diseases (PIDs). Methods CT-GPLB pathogenic diagnostic results of 109 patients with clinically suspected PIDs from March 2018 to August 2022 were retrospectively analyzed and compared with conventional pathogenic diagnostic results such as sputum, blood, and bronchoscopy. Results Among 109 cases of PIDs, 47 cases (43.1%) had identified pathogens. Among them, there were 24 cases of fungal infections (including 1 case of mixed infection with Gram-negative bacillus), 9 cases of bacterial infections, 12 cases of Mycobacterium tuberculosis infections, 1 case of viral infection, and 1 case of fast-growing Mycobacterium fortuitum infection. The pathogenic diagnosis rate of CT-GPLB was 42.2%, with one case showing positive acid-fast staining in sputum smear but negative in other examinations. The positive rates of CT-GPLB tissue culture, pathology exa-mination, and lung tissue smear were 21.1%, 28.4%, and 7.3%, respectively. The overall pathogenic diagnostic rate of CT-GPLB lung tissue was 42.2% (46/109), which was higher than that of sputum specimen examination (4.1% [3/73]), blood examination (3.1% [1/32]) and bronchoalveolar lavage fluid (9.8% [8/82]). The positive rate of CT-GPLB tissue culture was 21.1% (23/109), which was higher than that of sputum culture (2.7% [2/73]) and bronchoalveolar lavage fluid culture (7.3% [6/82]). Conclusion CT-GPLB tissue examination is of high clinical value in identifying the pathogens of PIDs, with a higher diagnostic rate compared to conventional pathogenic examination methods.