Inclusion Criteria:  Age from over 18 to under 75 years; Gastrointestinal stromal tumor at unfavorable anatomic sites of stomach preoperatively confirmed by endoscopy, ultrasound endoscopy, CT or MRI; Diameter of tumor size is ≥2cm and ≤5cm confirmed by contrast CT or MRI; Patients whose tumor is resectable by laparoscopic technique at preoperative assessment; No evidence of distant metastasis and tumor invading nearby organs at preoperative assessment; Performance status of 0 or 1 on ECOG (Eastern Cooperative Oncology Group) scale; ASA (American Society of Anesthesiology) score I, II, or III; Written informed consent.  Exclusion Criteria:  Women during pregnancy or breast-feeding; Severe mental disorder; History of previous upper abdominal surgery (except laparoscopic cholecystectomy); History of other malignant disease within the past five years; History of previous neoadjuvant imatinib therapy; History of unstable angina or myocardial infarction within the past six months; History of cerebrovascular accident within the past six months; History of continuous systematic administration of corticosteroids within the past month; Requirement of simultaneous surgery for other disease; Emergency surgery due to complication (bleeding, obstruction or perforation) caused by gastrointestinal stromal tumor; FEV1<50% of predicted value; Patients with GIST locates at favorable anatomic sites detected by contrast CT, MRI or ultrasound endoscopy at preoperative assessment; Patients with GIST diameter<2cm or>5cm detected by contrast CT or MRI; Presence of distant metastasis or tumor invading nearby organs at preoperative assessment.  Withdrawal Criteria:  Patients postoperatively confirmed as non-GIST case by pathology (These cases are enrolled in safe group for future statistic analysis); GIST at unfavorable anatomic site diagnosed before operation, while GIST at favorable anatomic site determined by intraoperative exploration; Patients confirmed as tumor rupture , metastasis or invading nearby organs intraoperately; Patients requiring simultaneous surgical treatment of other diseases; Sudden severe complications during the perioperative period (intolerable surgery or anesthesia), which renders it unsuitable or unfeasible to implement the study treatment protocol as scheduled; Patients confirmed to require emergency surgery by attending physicians due to changes in the patient's condition after inclusion in this study; Patients who voluntarily quit or discontinue treatment for personal reasons at any stage after inclusion in this study; Treatment implemented is proven to violate study protocol.