The clinical data of 2 patients with Chlamydia psitsiti pneumonia were collected， and the diagnosis and treatment process was summarized；the infection indicators， oxygenation function， dynamic changes of pulmonary imaging were analyzed；culture method，serological method， metagenomic next-generation sequencing technology （mNGS） and other etiological diagnostic methods were compared，and the effects of quinolones and tetracycline in the treatment of Chlamydia psittaci pneumonia were analyzed.

The first symptoms of two patients were fever， cough and expectum， and the disease progressed rapidly. Dyspnea developed on the 8th day and the 3rd day of onset， respectively. One patient developed acute respiratory distress syndrome（ARDS） on the 10th day of onset， and mechanical ventilation assisted treatment was used. The counts of white blood cells in blood routine examination of two patients were 12.69×10⁹·L^－1 and 4.4 ×10⁹·L^－1， and procalcitonin were 0.27 and 0.06 μg·L^－1， respectively. Routine culture of airway secretes and serological examination failed to identify the pathogen. The initial diagnosis of two patients was community acquired pneumonia， and the effect of empirical treatment with quinolones was not good. The mNGS method combined with bird contact history was used to finally confirm the diagnosis of Chlamydia psittaci pneumonia.The symptoms， signs and imaging abnormalities were significantly improved after treatment with tegecycline， a tetracycline antibiotic. The results of lung CT reexamination of 2 cases after 1 month follow-up showed that the lesions were basically absorbed.

The occurrence of Chlamydia psittaci pneumonia is related to the contact history of birds. The progress of the disease is often rapid. The mNGS technology can be used as a rapid etiological diagnosis method， which is conducive to the early diagnosis of Chlamydia psittaci pneumonia， the timely selection of sensitive antibiotics and the improvement of disease prognosis. A new generation of tetracyclines represented by doxycycline and tigecyclin has a positive effect on Chlamydia psittaci pneumonia.