Objective To explore the application value of multi-slice spiral CT and ultrasound combined with blood amylase examination in the diagnosis of severe acute pancreatitis in intensive care unit (ICU). Methods A total of 94 patients with severe acute pancreatitis who were treated inour hospital from May 2017 to May 2018 were enrolled in the study. All patients' gender, age ,indicators of clinical examination and imaging data were collected. According to the data, all patients were diagnosed as severe acute pancreatitis and then transferred to the ICU for treatment. The sensitivity and specificity of different methods for the diagnosis of severe acute pancreatitis were analyzed. Results The sensitivity and specificity of multi-slice spiral CT and ultrasound combined with blood amylase examination for the diagnosis of severe acute pancreatitis were 92.6% and 91.2%, respectively, which were significantly higher than those of the multi-slice spiral CT examination, ultrasound and blood amylase examination alone and those in pairs(P<0.05). In 94 patients with severe acute pancreatitis diagnosed by ultrasound examination, 78 cases were edematous, mainly charactering diffuse enlargement of the pancreas. In most patients, the parenchymal echo of the pancreas showed a uniform attenuation. In the plain scan of the CT, the pancreas was significantly enlarged, especially in the tail of the pancreas, and a little exudation was observed around the pancreas. After enhanced contrast, no obvious and abnormal enhancement of pancreatic thickening was observed in the arterial phase, venous phase and delayed phase. Conclusion Multi-slice spiral CT examination can display the anatomical location of the pancreas better and reflect the pathogenesis and severity of lesions. Combined with ultrasound and blood amylase, the sensitivity and specificity for the diagnosis of severe acute pancreatitis are the highest and more valuable in clinical.