Objective: To analyze the causes of upper gastrointestinal bleeding in patients with portal hypertension for investigating the relationship between varicosity at different positions of esophageal and gastric fundus vein and the causes of bleeding. Methods: One hundred and twenty-one patients with portal hypertension and upper gastrointestinal bleeding were divided into three groups according to the variceal position: esophageal varices group(varicose vein only seen in the esophagus, n=40), gastroesophageal varices group (varicose vein in both esophagus and stomach, n=48), gastric varices group (varicose vein only in the stomach, n=33). Stochasticly selected cases in each group were analyzed differentially for the cause of variceal bleeding. Results: The top three bleeding causes in esophageal varices group were variceal rupture bleeding (80.0%, 32/40), peptic ulcer bleeding（10.0%, 4/40）and portal hypertensive gastropathy and other causes (all were 5%, 2/40); in gastroesophageal varices group were variceal rupture bleeding (83.3%, 40/48),peptic ulcer bleeding (8.3%, 4/48) and portal hypertensive gastropathy (6.3%, 3/48); in gastric varices group were peptic ulcer bleeding (54.5%, 18/33), variceal rupture bleeding(18.2%, 6/33), and other causes(15.2%, 5/33). The incidences of variceal rupture bleeding as the cause of bleeding in esophageal varices group and gastroesophageal varices group were significantly higher than that in gastric varices group （P<0.001）. Conclusions: Portal hypertensive patients with varicosity at different positions may have different causes of upper gastrointestinal bleeding. The position of variceal veins has a guiding significance for differetia-ting the cause of upper gastrointestinal bleeding in such patients.