Abstract： Objective To investigate the diagnosis of acute superior mesenteric venous thrombosis(MVT) by ultrasonography. Methods Seventeen patients with MVT were confirmed by operation or CT scanning and followed-up, whose ultrasonographic features were analyzed retrospectively. Results Ultrasonographic features of seventeen patients with MVT were enlarged superior mesenteric vein filled with hypoecho without flow signals( n =9) ,portal vein and(or) splenic vein filled with hypoecho without flow signals (n =4), intestine wall thickening and intestine distension( n =2) and ascites( n =2). The accuracy of ultrasonographic examination for SMV was 65％ (11/17). According to MVT with or without splenic or portal vein involvement,MVT were been classified as two type:large vessel type(n =10) and small vessel type(n =7). The accuracy of ultrasonographic examination for large vessel type and small vessel type were 90％ (9/10) and 29％ (2/7) ,respectively. Patient with large vessel type of MVT were easy to be diagnosed by ultrasonography than those with small vessel type( x2 =3.41, P ＜ 0. 05 ). Conclusion Ultrasonography was valuable in diagnosis of MVT, and it played more important role in diagnosis of large vessel type of MVT.