This study describes the characteristics of severe systemic lupus erythematosus (SLE) patients who visited the emergency department of the Shanghai Renji Hospital, and the aim is to identify the causes, the outcome, and the prognostic factors. SLE patients who visited the emergency department between January 2007 and August 2010, and who were subsequently hospitalized or who died in emergency department, were included in this retrospective study. Of the total 131 SLE emergency events, overall mortality was 16.8%. Older age (≥45 years), longer duration of disease, presence of pulmonary hypertension, renal insufficiency, and invasive infections are risk factors. Higher organ damage index (SLICC, 3.86 ± 2.14 vs. 0.93 ± 1.14, p < 0.001) but relatively lower disease activity (SLEDAI, 11.5 ± 7.7 vs. 16.5 ± 9.0, p = 0.015) were the characteristics of the deceased when compared with the survivors. Recent-onset (duration of disease ≤3 months) SLE accounts for 32.1% of the patients in emergency, and this group showed a distinctive pattern of younger age with higher frequencies of neuropsychiatric and hematologic manifestations. A good short-term outcome with a 95.2% survival rate can be observed in such patients. Older age, longer disease duration and cumulative damage of vital organs determine the short-term outcome of severe SLE in the emergency department. Recognizing disease patterns and objective prognostic parameters may help physicians to provide better care, based on a risk-fitted approach, for the SLE patients in emergencies.