Objective To evaluate the diagnostic value of acetic acid spray combined with narrow-band imaging ( NBI) for early gastric cancer and precancerous lesion. Methods A total of 136 gastric cancers and precancerous lesions from 132 patients detected by screening endoscopy from November 2015 to November 2017 in Guangming Chinese Medicine Hospital of Pudong New Area, Shanghai were enrolled in this study, and were divided into NBI group, acetic acid spray group, and acetic acid spray combined with NBI group ( combination group) . The image clarity, microsurface pattern, microvascular pattern, demarcation line, and mucosal whitening time were observed, and value of the 3 methods in diagnosis of early gastric cancer and precancerous lesions was analyzed. Results Image clarity of micro glandular in combination group was significantly better than that in NBI group and acetic acid spray group (χ2=8. 766, P=0. 003;χ2=5. 273, P=0. 022) , and image clarity of microvascular in combination group was significantly better than that in NBI group (χ2=7. 457, P=0. 006) . The overall diagnostic coincidence rate with pathology of combination group, NBI group, and acetic acid spray group was 91. 9％(125/136), 85. 3％(116/136), and 89. 7％(122/136), respectively. The diagnostic sensitivity of irregular or missing microsurface, irregular or missing microvascular, obvious demarcation line, mucosal whitening time <30 s for carcinoma ( including high grade intraepithelial neoplasia, early carcinoma and infiltrating carcinoma ) were 92. 3％, 91. 3％, 92. 3％ and 90. 4％, respectively, in the combination group, and the diagnostic specificity of above indicators were 93. 8％, 93. 8％, 96. 9％ and 90. 6％, respectively, accuracy were 92. 6％, 91. 9％, 93. 4％ and 90. 4％, respectively. For observation of microsurface, the combination group was superior to the NBI group (χ2 =7. 378, P=0. 007) , but there was no significant difference compared with the acetic acid spray group (χ2=0. 427, P=0. 513);the acetic acid spray group was superior to the NBI group (χ2=4. 405, P=0. 036) . For observation of microvascular, the combination group was not significantly better than the NBI group (χ2=2. 398, P=0. 122). For observation of demarcation line, the combination group was not significantly better than the NBI group (χ2=2. 722,P=0. 099) and the acetic acid spray group (χ2=0. 216, P=0. 642). There was no difference between the acetic acid spray group and the NBI group (χ2=1. 433, P=0. 231) in observation of demarcation line. Conclusion Acetic acid spray combined with NBI has a good consistency with pathological results with high diagnostic sensitivity and specificity, and can clearly show microsurface of early gastric cancers and precancerous lesions compared to single NBI.