Objective To explore the use of gastroscopy and CT for staging and clinical guiding to the surgical therapy of advanced gastric cancer.Methods The preoperative gastroscopic and CT classification and the results of operative classfication of 182 cases of advanced gastric carcinoma were compared.Results The resection rate for low and undifferentiated adenocarcinoma and mucinous carcinoma on gastroscopic biopsy was low(64.1%),and the rate for diffuse infiltrative gastric carcinoma(6.7%)was significantly lower than that of mass tumor type(66.7%)and ulcerative type(61.8%).The total accuracy rate of CT staging was 91.21%.Sensitivity rate of CT diagnosis of perigastric invasion and/or metastasis was 72.22%.For lymph node staging the accuracy rate of CT was 74.2%,sensitivity rate was 74.1% and specificity rate was 74.3%.CT diagnosis of lymph node groups was blur.Conclusions Gastroscopy has an unreplaceable role in the final diagnosis of advanced gastric cancer and has significance for gross tumor grading,histologic biopsy diagnosis can be as a guide to dicide the treatment modality of advanced gastric cancer.CT has high degree of value for accuracy of clinical staging,and diagnosis of invasion of adjacent organs and lymph node metastasis.CT is superior to gastroscopy for judgement of resectability.Therefore,preoperative CT is a valuable guide for surgical treatment of advanced gastric cancer.