To summarize the causes of death and to analyze the risk factors in a surgical intensive care unit (SICU). The relevant information of patients died in the SICU of Xijing Hospital of Fourth Military Medical University in past 15 years (from December 1999 to February 2015) was retrospectively analyzed. The gender, age, reason and date of hospitalization, date of transfer SICU, past medical history, whether or not admitted directly from emergency department or transferred from other department, operated or not, date of death, the main cause of death, acute physiology and chronic health evaluation II (APACHE II) score, the history of undergoing mechanical ventilation, continuous renal replacement therapy (CRRT), or antifungal therapy, as well as the ratio of the patients with body temperature higher than 39 °C, white blood cell (WBC) count higher than 10 x 10⁹/L, platelet (PLT) count below 100 x 10⁹/L, albumin (Alb) below 35 g/L of two periods, namely from December 1999 to July 2007 (the first period), and from August 2007 to February 2015 (the second period) were compared. The above parameters were compared with those of 201 survivors in SICU, and the risk factors leading to death were analyzed by logistic regression. From December 1999 to February 2015, 4 317 patients were taken care of in the SICU. Among them, the number of death was 186, and the mortality rate was 4.3%. In the first time period (from December 1999 to July 2007), the total number of patients was 1 356, and the number of death were 109 (the mortality rate was 8.0%). In the second period, i.e. from August 2007 to February 2015, the number of SICU patients was 2,961, and 77 died (the mortality rate was 2.6%). The difference of mortality rate between the two periods was statistically significant (χ² = 66.707, P = 0.001 ). The death rate of patients transferred directly from emergency department in the first period was 79.8% (87/109), and it was lower in the second period (51.9%, 40/77, χ² = 16.181, P = 0.001 ). The death rate of the patients with blood A1b below 35 g/L in the second period (59.7%, 46/77) was higher than that of the first period (41.3%, 45/109, χ² = 6.151, P = 0.017). The top three causes of death from December 1999 to February 2015 were sepsis (38.2%), trauma (16.7%), and operation for cancer (14.0%). In the first period, the top three causes of death were sepsis (35.8%), trauma (22.0%), and operation for cancer (13.8%). In the second period, the top three causes of death were sepsis (41.6%), damage of the central nervous system (16.9%), and operation for cancer (14.3%). Top three reasons for SICU admission were trauma (29.03%), abdominal pain (20.97%) and other reasons (18.82%). Top three departments from which the patients were transferred were the emergency department (19.35%), orthopedics department (17.20%), and hepatobiliary department (16.13%). Logistic regression analysis showed that age [odds ratio (OR) = 2.025, 95% confidence interval (95% CI) = 1.500-2.734, P = 0.000], mechanical ventilation (OR = 3.514, 95% CI = 1.701-7.259, P = 0.001), CRR T (OR = 5.604, 95% CI = 3.003-10.459, P = 0.000 ), body temperature higher than 39 °C (OR = 1.992, 95%CI = 1.052-3.771, P = 0.034) were the risk factors of death in SICU patients. Sepsis and severe trauma are the leading causes of death in severe SICU patients, to whom with risk factors of death enough attention should be given.