Objectives To evaluate the application of preoperative endoscopic ultrasonography ( EUS) in assessment of invasive risk and selection of therapeutic modalities for gastric stromal tumors ( GST).Methods The clinical data of 135 patients with GST admitted in our hospital from January 2011 to January 2012 were retrospectively analyzed.The invasion extent of GST was assessed by image of EUS before surgery, and compared with pathological results after surgery; the Fletcher 4-tier system was used for predicting the aggressiveness of GST.The selection of therapeutic modalities in 38 patients, who underwent surgical treatment was analyzed.Results No specific clinical manifestations were noticed , but some patients with enormous GST had symptoms of ulcer , hematemesis , and melena.Among 135 patients 97 cases received conservative treatment and followed up;in remaining 38 cases, according to invasion risk assessed by EUS, there were 9 cases in low risk, 18 in intermediate risk and 11 in high risk.The surgical modalities were selected based on the risk assessment:endoscopic therapy was performed in 15 cases, laparoscopic with gastroscopic surgery in 17 cases and laparotomy in 6 cases.The coincidence rate of diagnosis between preoperative EUS and postoperative pathological examination was 79.0%.Conclusions Preoperative endoscopic ultrasonography is of value in assessment of invasion risk and selection of appropriate therapeutic modalities for gastric stromal tumors.