Abstract：Objective：To collect the nutritional status of patients with idiopathic pulmonary fibrosis(IPF)，and to analyze the clinical characteristics and influencing factors in patients with idiopathic pulmonary fibrosis complicated with malnutrition. Methods： The nutritional status， clinical characteristics and related factors of 170 IPF patients in four hospitals were evaluated by Mini Nutritional Assessment(MNA). Results：A total of 41 cases were detected as malnutrition，accounting for 24.1%. In the IPF complicated with malnutrition group，the acute exacerbation times in recent one year，and the scores of chronic obstructive pulmonary disease(COPD) assessment test(CAT)， modified Medical Research Council(mMRC) dyspnea scale and the St. George's Respiratmy Questionnaire(SGRQ) including activity ability，disease influence and total score were higher than those in the IPF group，differences being significant(P＜0.05)；the body mass index(BMI)，the six minute walk test(6MWT)，the lung function including FEV1，FVC and DLco%，and the Mos Item Short from Health Survey(SF-36) scores including physiological function， social function， emotional function and mental health were lower， differences being significant(P＜0.05). There was no significant difference being found in the comparison of course of disease， Chinese medicine syndrome types and other indexes between the two groups(P＞0.05). Conclusion：The proportion of IPF patients with malnutrition is relatively high. The occurrence of malnutrition is related to the clinical symptoms，activity ability，quality of life， acute exacerbation times， lung function and other factors of IPF patients. The IPF patients with malnutrition have more severe clinical symptoms，and poorer activity ability，health- related quality of life and lung function，with increased risk of acute exacerbation.