Abstract: Objective To improve the clinical diagnosis and treatment of nonspecific interstitial pneumonia(NSIP) and cryptogenic organizing pneumonia(COP) by comparing the clinical and radiological features and the lung function of such patients. Methods The clinical and radiological features and the lung function of 7 biopsy-proved NSIP patients and 12 biopsy-proved COP patients admitted to our hospital from March 2007 to June 2012 were retrospectively analyzed. Results The clinical symptoms of NSIP and COP patients were manifested as cough, dyspnea and expectoration.The systemic symptoms such as fever, acratia and weight loss were severer in COP patients than in NSIP patients.The lung function was manifested as reduced restrictive ventilation function and diffusion function both in NSIP patients and in COP patients.The TLC%, FVC%, FEV₁% and D_LCO% were significantly lower in COP patients than in NSIP patients(P＜ 0.05).The chest CT scanning showed ground-glass shadows in both lower lungs of 6 NSIP patients and consolidated shadows in subpleural or perilobular branches of 11 COP patients. Conclusion No significant symptoms can be found in the respiratory system of COP and NSIP patients.However, the systemic symptoms are severer in COP patients than in NSIP patients.CT scanning shows that the restrictive ventilation function and diffusion function are significantly lower in NSIP patients than in COP patients.Lung biopsy contributes to the diagnosis of NSIP and COP.