By randomly selecting the de-identified electronic medical records of acute pancreatitis in a hospital in Liaoning Province, the paper builds a prediction model of acute pancreatitis patients' hospital stay based on the regression analysis of Support Vector Machine(SVM) and summarizes factors influencing hospital stay. The prediction of the constructed regression model is reliable with good accuracy and generalization. It is indicated that the key after the model is established lies in the selection of the characteristic variable.