Objective To investigate clinical relevance of U1-nuclear ribonucleoprotein antibody (anti-U1 RNP) in Chinese patients with systemic sclerosis (SSc). Methods In total, 131 Chinese patients with SSc were prospectively and consecutively recruited into Scleroderma Trials and Research Group sponsored by European League Against Rheumatism (EUSTAR) from clinical database of Peking Union Medical College Hospital ( PUMCH). Their clinical features, visceral lesions and laboratory findings including detection of anti- U1 RNP were recorded. Relevance between existing anti-U1 RNP and clinical characteristics and other laboratory indicators of SSc was analyzed statistically. Results Eighty-seven of the 131 patients presented as diffused SSc (dSSc) , 36 limited SSc ( lSSc) and eight SSc/systemic lupus erythematosus (SLE) overlap syndrome, with positive rate of anti-U, RNP of 28. 2 (37/131) percent in patients with SSc. Positive rate of anti-U1 RNP in dSSc was similar to that in lSSc groups [28. 7% (25/87) and 25. 0% ( 9/36 ) , respectively, P = 0. 673]. But significantly higher prevalence of pulmonary arterial hypertension and cardiac involvement, and less white blood cell and platelets counts were observed in the patients with positive anti-U1 RNP than in those with negative anti-U1 RNP (all P < 0. 05 ). There was no statistically significant difference in skin sclerosis score and prevalence of arthritis, myositis and interstitial lung disease was observed between those with positive and negative anti-U1 RNP ( P > 0. 05 ) . Detection rate of anti-DNA topoisomerase I ( Scl-70 antibody) was higher in SSc patients with negative anti-U, RNP. Conclusions U1 RNP antibody is a common antibody in Chinese patients with SSc, and detection for it combined with other autoantibodies will be helpful for diagnosing of SSc and predicting development of pulmonary arterial hypertension, cardiac and hematological involvements in them.