Objective To observe the characteristic of precancerous lesions and early gastric carcinoma with narrow belt imaging technology. Methods The 74 patients were enrolled in this study. The same case was used as self-control. The operation was made in pain-less under anesthesia. When the mirror was advanced to the duodenal descending segment, an ordinary microscope mode was used and the mirror was back to Mallory, the lesions found were recorded, the image was zoomed in with low-fold and observed (1.4,1.6,1.8 times). Suspicious lesions were collected and biopsies were made. Results Chronic gastritis could be commonly found in type A and AB. Mild in-testinalization and mild atypical hyperplasia could be commonly found in mixed type holding type C, type BC and AB. Moderate atypical hy-perplasia could be found in type CD and AC, and heavy atypical hyperplasia in type CD and D. Early gastric cancers (superficial depressed) were seen in type BC and irregular thick type A. Advanced gastric cancers were in type CD, D and C. Helicobacter pylori infection were common in type A and B. Protruded type, sunken type were not easily missed with common endoscopic and NBI. But "for ordinary focus of infection, it was easily missed with common endoscopic, while less with NBI. Conclusion NBI is a simple and safe method, which can be used to find precancerous lesions and early gastric cancer lesions more easily. It will enlaance the diagnosis rate of precancerous lesions and early gastric cancer as positive rate of biopsy was markedly improved.