Abstract: Objective To study the diagnostic value of alveolar nitric oxide concentration (CANO) and 25OH-D in systemic sclerosis-associated interstitial lung diseases. Methods From June 2015 to December 2016, 26 cases with systemic sclerosisassociated interstitial lung disease, 24 cases with systemic sclerosis without interstitial lung disease and 50 healthy controls were recruited in our hospital. Their serum 25OH-D levels and CANO were detected and compared between 3 groups. Results The serum 25OH-D level of systemic sclerosis-associated interstitial lung diseases patients (23.4±4.9 nmol/L) was lower than those of systemic sclerosis without interstitial lung diseases patients (30.9±4.1 nmol/L) and healthy controls (55.6±11.3 nmol/L) (P< 0.05, respectively). CANO in patients with systemic sclerosis-associated interstitial lung disease (11.1±4.7 mm³/m³) was higher than those in the patients without interstitial lung disease (5.7±3.4 mm³/m³) and healthy controls (2.3±1.2 mm³/m³) (P< 0.05, respectively). Conclusion Compared with interstitial lung disease patients and healthy controls, 25OH-D in patients with systemic sclerosis- associated interstitial lung disease decreases significantly, and CANO increases significantly. Serum 25OH-D and CANO are valuable for the diagnosis of systemic sclerosis-associated interstitial lung diseases.