Due to the limitations of traditional laboratory methods (TMs), identification of causative pathogens of numerous pulmonary infections (PIs) remains difficult. This study evaluated the value of metagenomic next generation sequencing (mNGS) in the identification of various respiratory pathogens. A total of 207 patients with TMs and mNGS data were collected for this retrospective study. TMs included sputum culture, blood, and bronchoalveolar lavage fluid (BALF) analysis, or polymerase chain reaction analysis of throat swabs. Otherwise, BALF was collected and analyzed using mNGS. For bacterial pathogens, sensitivities of mNGS as compared to TMs were 76.74 % and 58.14 % (P=0.012). For fungal pathogens, the detection rate of mNGS sensitivity was higher as compared to that of TMs (93.68 % vs 22.11 %; P<0.001). The positive predictive value and negative predictive value were also greater for mNGS. Use of mNGS for BALF analysis offers good specificity and thus facilitates to the clinical diagnosis of PIs.