【Abstract】 Objective To compare the effects of norepinephrine (NE) combined with levosimendan (LEVO) or dobutamine (DOB) in a porcine model of septic shock. Methods Twelve pigs were anesthetized and mechanically ventilated. Peritonitis model was established via inoculating the autologous feces (1 g/kg) into peritoneal cavity. When mean arterial pressure (MAP) decreased to less than 60 mmHg, animals were randomly assigned to receive NE + LEVO 0.4 ?g/kg/min (LEVO group, n=6) or NE + DOB 10 ?g/kg/min (DOB group, n=6) to maintain MAP between 65 and 75 mmHg. HR (heart rate), MAP, MPAP (mean pulmonary artery pressure), cardiac output (CO), pHa, and plasma levels of lactate (Lac), TNF-?, IL-6, IL- 10, metabolites of nitric oxide (NOax) were measured before model institute (T1), shock time (T2), shock 6 h time (T3), and shock 12 h time (T4). Oxygen index (PaO2/FiO2) and oxygen delivery (DO2) were calculated. NE requirements were recorded. Results There were no significant differences between the two groups with respect to body weight, time to the onset of septic shock, NE requirements, MAP, MPAP, pHa, Lac, CO, IL-10, PaO2/FiO2, and DO2 (P>0.05). Compared with DOB group, LEVO group had lower HR at T3 and T4, decreased plasma level of TNF-? at T3, and decreased plasma levels of NOax and IL-6 at T4, respectively (P<0.05). Conclusion Compared with NE combined with DOB, NE combined with LEVO can reduce HR and inflammatory responses in a porcine model of septic shock.