Objective To explore the effect of nanow-band imaging (NBI) combined with magnifying endoscopy (ME) in early diagnosis of gastric cancer,and to observe whether it is helpful for inexperienced endoscopists to diagnose.Methods From April 2015 to October 2017,a total of 480 lesions were selected as research objects which were detected in the normal white light endoscopy (WLE).Pathological examination was used as the gold standard for diagnosis.3 experienced doctors were selected to read the endoscopy films.40 intern endoscopy doctors were selected to read the endoscopy filins at the same time after simple training.80 WLE images and narrowband imaging technology combined with magnifying endoscopy (ME-NBI) images were randomly selected to hold a film reading meeting.Real-time voting was used to judge the nature of lesions.Results The accuracy,sensitivity,specificity false positive rate and false negative rate of ME-NBI were 97.9％ (470/480),96.8％ (120/124),98.3％ (350/356),1.7％ (6/356),3.2％(4/124).And WLE values were 91.7％ (440/480),80.6％ (100/124),89.9％ (320/356),10.1％ (36/356),19.4％ (24/124),respectively.The diagnostic accuracy,sensitivity and specificity of ME-NBI were significantly higher than those of WLE (x2 =18.989,16.104,15.859,P≤0.05),and the false positive rate and false negative rate were significantly lower than those of WLE (x2 =22.772,16.104,P ≤ 0.05).The diagnostic results of ME-NBI of 40 endoscopy interns were significantly better than those of WLE (t =11.467,16.188,P ≤0.05).The diagnostic results of NBI by 40 interns were significantly better than that of WLE (t =11.467,16.188,P ≤ 0.05).Conclusions The accuracy of ME-NBI in screening early gastric cancer is satisfactory,and it has certain diagnostic value for inexperienced doctors.