Objective To explore the safety and long-term results of preoperative imatinib mesylate administration (IM) in patients with locally advanced gastrointestinal stromal tumors (GIST).Methods From Sep 2009 to Nov 2016,locally advanced GIST patients treated in Fujian Medical University Cancer Hospital were analysed retrospectively.Result 34 patients were included.Preoperative median IM treatment was 27 weeks(range 12-71 weeks).65％ patients had a partial response to IM,35％ showed stable disease.All patients underwent surgical R0 resection.The complication rate was 9％ and no death occurred within 30 days post operation.The median follow-up time was 62.2 months (range of 13-89 months).20 patients continued to take imatinib orally,14 patients did not.The 3 year survival rate of patients undergoing surgery was 67％.Univariate analysis showed that tumor location,preoperative imatinib effect,pathology,targeted therapy after surgery were factors affecting prognosis.Multivariate analysis show that the independent risk factors affecting prognosis were tumor location,pathology,targeted therapy after surgery.Conclusion In locally advanced GISTs,preoperative IM is useful and safe that can effectively decrease tumor size,facilitating resection.