Psittacosis is a infectious disease caused by Chlamydia psittaci (C. psittaci), which presents as pneumonia in humans. The diagnosis of psittacosis is challenging, however, Metagenomic next-generation sequencing (MNGS) is very efficient. Herein we documented the clinical characteristics of two patients with severe C. psittaci pneumonia who were admitted to the Intensive Care Unit. C. psittaci nucleic acid sequences were detected by MNGS of bronchoalveolar lavage fluid from both patients. Doxycycline was administered and the treatment was effective. Implementation of MNGS is helpful for the early identification of pathogens, shortening the diagnosis and treatment time, and improving the prognosis of patients.