Abstract: Objective To explore the effect of endoscopic ultrasonography (EUS), white light endoscopy (WLE), magnifying endoscopy combined with narrowb and imaging (ME-NBI) in the diagnosis of depth of invasion of early gastric cancer. 
Methods A total of 78 patients with early gastric cancer treated in Hebei Petro China Central Hospital were selected, 60 normal examiners were selected as controls, and the accuracy of EUS, WLI, ME-NBI alone and in combination in diagnosing the depth of invasion was compared. Logistic regression analysis was used to analyze the factors affecting the accuracy of EUS, WLI and ME-NBI in combination in the diagnosis of infiltration depth. 
Results Pathological results showed that there were 50 patients with T1a and 28 patients with T1b. In patients with T1a lesions, the combined diagnostic accuracy of EUS, WLI and ME-NBI was 92.00%, which was significantly higher than that of EUS and WLI alone (P＜0.05). In patients with T1b lesions, the combined diagnostic accuracy of EUS, WLI and ME-NBI was 92.86%, which was significantly higher than that of WIL alone (P＜0.05). The accuracy rate of EUS, WLI and ME-NBI in combination in diagnosing the depth of invasion in patients with lesion size ≥2 cm was 77.29%, which was significantly lower than that in patients with lesion size <2 cm (P＜0.05). The accuracy rate of EUS, WLI and ME-NBI in combination in the diagnosis of the depth of infiltration in patients with depressed form was 66.67%, which was significantly lower than that in patients with raised and flat form (P＜0.05). The accuracy rate of EUS, WLI and ME-NBI incombination in the diagnosis of the depth of invasion in the lesions of the cardia and fundus of the stomach was 76.92%, which was significantly lower than that in the lesions of the gastric body and the gastric antrum and pylorus (P＜0.05). Multivariate logistic regression analysis showed that the size, shape and location of the lesion were the influencing factors of the accuracy of EUS, WLI and ME-NBI in combination in the diagnosis of the depth of invasion (P＞0.05). 
Conclusion The combined detection of EUS, WLI and ME-NBI has high value in the diagnosis of the depth of invasion of early gastric cancer, and the accuracy of the combined diagnosis of EUS, WLI and ME-NBI is affected by the size and shape of the lesion. 

Key words: sstomach neoplasms, endosonography, white light endoscopy, magnifying endoscopy