Abstract: 50 cases of smooth muscle tumor in gastrointestinal tract were analysed，including 20 cases in stomach，5 cases in duodenum, 10 cases in jejunum，6 cases in ileum and 9 cases in the large intes-tine. 29 cases belong to benign tumor and 21 cases leiomyosarcoma. The clinical diagnosis rate is lower to the gastroenteric leiomyoma, this disease must be thought in the patient who have abdomi-nal pain，almentary canal bleeding and abdominal mass. The authors suggest that (1) mitotic figures (≥1/10 HPF)，(2)cell anaplasia，(3)tumor size >7cm，(4)infiltration of tumor cell into the neigh-bouring tissue, (5) presence of necrosis may be considered as the criteria for diagnosis. The tumors possess the first item or two among the rest four item can be diagnosed the malignant smooth tu-mors of the gastrointestinal tract.