Objective To explore the diagnostic value of endoscopic narrow-band imaging technique combined with indigo carmine staining on Helicobacter pylori (Hp)-associated gastric cancer. Methods Clinical data of 96 patients with Hp-associated gastric diseases admitted to the hospital from June 2020 to January 2022 were retrospectively analyzed. All patients underwent white light endoscopy, endoscopic narrow-band imaging and indigo carmine staining, with pathological examination result as the gold standard. The differences in diagnostic value of the above examination methods and the differences in imaging quality scores of the above methods were compared on patients with Hp-associated gastric cancer. Results Pathological result showed that 37 cases of gastric cancer and 59 cases of non-gastric cancer were confirmed among 96 patients with Hp-associated gastric diseases. The diagnostic accuracy of endoscopic narrow-band imaging and endoscopic narrow-band imaging combined with indigo carmine staining in patients with Hp-associated gastric cancer was higher than that of white light endoscop. The diagnostic Kappa values of the three were 0.675, 0.869, and 0.934, endoscopic narrow-band imaging, endoscopic narrow-band imaging combined with indigo carmine staining showed high consistency with pathological results (Kappa>0.75). The scores of lesion contour, microvascular morphology and gastric pit morphology of endoscopic narrow-band imaging and endoscopic narrow-band imaging combined with indigo carmine staining were higher than those of white light endoscopy, and the above scores of endoscopic narrow-band imaging combined with indigo carmine staining were higher than those of endoscopic narrow-band imaging. Conclusion Endoscopic narrow-band imaging technique combined with indigo carmine staining is valuable in the diagnosis of Hp-associated gastric cancer and can obtain clear images.