Objective To evaluate 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 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, micro surface, microvascular, demarcation line, and mucosa whitening time was observed, and values of the 3 methods in diagnosis of early gastric cancer and precancerous lesions were analyzed. Results Image clarity of micro surface 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 micro surface, irregular or missing microvascular, obvious demarcation line, mucosa whitening time<30 s to carcinoma (including high grade intraepithelial neoplasia, early carcinoma and infiltrating carcinoma) was 92.3%, 91.3%, 92.3% and 91.4%, respectively, in the combination group, and the diagnostic specificity of above indicators was 93.8%, 93.8%, 96.9% and 90.6%, respectively, accuracy rate was 92.6%, 91.9%, 93.4% and 90.4%, respectively. For observation of micro-surface, the combination group was superior to NBI group (χ2=7.378, P=0.007), while was no 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). Conclusion Acetic acid spray combined with NBI has a good consistency with pathological results with high diagnostic sensitivity and specificity, and can clearly show micro surface of early gastric cancers and precancerous lesions compared to signal NBI.