[Objective]To explore the value of serum ascites albumin gradient(SAAG)in the etiological diagnosis of ascites. [Methods]We retrospectively analyzed 80 outpatients and inpatients with ascites and divided them into portal hypertension related ascites group(42 cases)and non-portal hypertension related ascites group(38 cases),calculated the SAAG through the concentration of serum albumin and ascitic albumin taken at the same day,comparing the relationship between diagnosis and SAAG of the two groups. [Results]SAAG of the portal hypertension group was significantly higher than the non-portal hypertension group(P0.01). [Conclusion]SAAG is valuable for the diagnosis of portal hypertension ascites and non-portal hypertension ascites,however,it cannot completely replace other inspection methods.It is necessary to improve the ascites diagnosis rate together with other inspection methods.