Abstract: Objective　To investigate the differential diagnosis significance of serum lipase （LPS） for acute pancreatitis （AP） in patients with acute abdominal pain. Methods　A total of 598 patients with acute abdominal pain were classified into AP group （192 cases） and non-AP （NAP）group （406 cases），including cholecystolithiasis （30 cases），intestinal obstruction （15 cases），acute cholecystitis （10 cases），abdominal trauma （9 cases），pancreas malignancy （6 cases），special abdominal pain （299 cases），diabetes mellitus （6 cases），upper digestive tract disease （11 cases），pulmonary disease （9 cases） and acute renal failure （11 cases）. Receiver operating characteristic（ROC） curve was set up， and the sensitivity， specificity， positive and negative predictive values were analyzed for LPS and serum amylase （AMY）. Results　Serum AMY and LPS levels in AP group were significantly higher than those in NAP group（P<0.01）. When the cut-off values of LPS and AMY were both set to 3 times of upper limit of normal reference range （180 and 300 U/L）， the sensitivities were 87.5% and 62.5%， the specificities were 89.4% and 95.3%， the positive predictive values were 80.0% and 86.3%， the negative predictive values were 94.7% and 88.2%， respectively. The areas under ROC curve for LPS and AMY were 0.959 and 0.921. There was positive correlation between serum AMY and LPS levels（r＝0.90）. Conclusions　Serum LPS has clinical significance in AP diagnosis， and is a better marker than AMY.

Key words: Lipase, Amylase, Acute pancreatitis