Abstract： Obejective To prospectively evaluate the clinical value of different magnifying chromoendoscopic(MCE) methods in screening gastric precancerous lesions and early cancers.Methods Between March 2010 and October 2011, among all the patients aged over 40 who received esophagogastroduodenoscopy at Zhongshan hospital,Fudan University,suspicious lesion was detected in 699 patients,who were randomly assigned to three groups:epinephrine dye (n=240),indigo carmine dye (n=246),and acetic acid-indigocarmine mixture dye (n=213).Diagnosis was made according to surface patterns and microvessels of the lesion.Pathological diagnosis was used as the gold standard.The concordance between endoscopic diagnosis and pathological diagnosis was evaluated through the agreement (Kappa) test.McNemar Paired chi-square test was used to compare the concordance of three MCE methods,regular white light,magnification alone,and NBI magnifier before and after MCE.Results Pathological examination showed inflammatory lesions in 415 patients,intestinal metaplasia in 190,low grade intra-epithelial neoplasia in 17,and high grade intra-epithelial neoplasia or early cancer in 77.The percentage of patients with consistent endoscopic and pathological diagnosis was 77.1％ (185/240) for epinephrine dye,80.5％(198/246) for indigo carmine dye,and 81.2％ (173/213) for aceticacid-indigocarmine mixture dye.Kappa values were 0.579,0.502,and 0.667 respectively(all P＜0.01 ).For the screening of high grade intra-epithelial neoplasia or early cancer,the diagnostic sensitivities were 84.0％,83.3％,and 92.9％,respectively,and the specificities were 98.6％,97.3％,and 98.4％.All the three chromoendoscopic methods improved the diagnostic accuracy for precancerous lesions compared with conventional gastroscopic observation with white light (all P＜0.01 ).Indigo carmine and acid-indigocarmine mixture dye improved the diagnostic accuracy of magnification alone (both P＜0.05).There was no significant difference in diagnostic accuracy between each MCE method and magnifying NBI observation (all P＞0.05).Conclusion NBI magnification and all the three MCE methods may improve the diagnostic accuracy of early gastric cancer and precancerous lesions.