Objectives: To estimate the prevalence of pulmonary arterial hypertension (PAH) and risk factors for PAH in patients registered in the Chinese SLE Treatment and Research group (CSTAR) database, the first online registry of Chinese patients with systemic lupus erythematosus (SLE). Methods: A prospective cross-sectional study of patients with SLE was conducted using the CSTAR registry. Resting transthoracic echocardiography was used to estimate pulmonary artery pressure (PAP); PAH was defined as systolic PAP (PASP) >= 40 mmHg. Patients with interstitial lung disease, valvular disease or cardiomyopathy were excluded because of disease influence on PAP. We explored potential risk factors for PAH including patient characteristics, organ involvement, laboratory findings and SLE disease activity. Results: Of 1934 patients with SLE, 74 had PASP with 54.2 +/- 17.1 (40,106) mmHg and were diagnosed with probable PAH. The incidences of lupus nephritis, pleuritis, pericarditis, hypocomplementemia, anti-SSA, and anti-ribonucleoprotein (RNP) were significantly higher in patients with PAH than in those without (p<0.05). SLE disease activity was significantly higher in patients with PAH than in unaffected patients (p<0.05). Multivariate analysis indicated that pericarditis (odds ratio (OR) = 4.248), pleuritis (OR = 3.061) and anti-RNP (OR = 2.559) were independent risk factors for PAH in patients with SLE (p<0.05). Conclusions: The possible prevalence of PAH was 3.8% in Chinese patients with SLE in the CSTAR registry. The significant association of pericarditis, pleuritis and anti-RNP positivity with PAH suggests that higher disease activity and vasculopathy may both contribute to the development of PAH in SLE, which need be treated aggressively to improve prognosis.