Abstract: OBJECTIVE To explore the relationship between Helicobacter pylori infection and the occurrence and development of gastric cancer so as to provide guidance for clinical prevention of gastric cancer. METHODS The gastric cancer tissue specimens were collected from 90 patients with gastric cancer who were treated in the hospital from May 2014 to May 2015 and were chosen as the study group, and the paracancerous tissue specimens were obtained from 40 patients with gastric cancer and were set as the control group, all of which were normal tissues through the pathological diagnosis. The specimens were detected by using relative quantitative real-time PCR method, H.pylori relative infection amount of the two groups of patients was observed, the relationship between H.pylori infection and the occurrence and development of gastric cancer was analyzed, and the statistical analysis was performed with the use of SPSS19.0 software. RESULTS H.pylori relative infection amount of the study group was (9.5±2.1), significantly higher than (4.5±1.2)of the control group (P<0.05). There was significant difference in the H.pylori relative infection amount among the patients with different clinical TNM stages, lymph node metastasis, or depths of invasion in the study group (P＜0.05). There was no significant difference in the incidence rate of H.pylori infection in the patients with different genders, age, clinical TNM stages, lymph node metastasis, invasion depths, or sites of gastric cancer between the two groups. CONCLUSION H.pylori infection is closely associated with the occurrence and development of gastric cancer, it may involve in the invasion depth and metastasis and clinical stage of the gastric cancer, and affect the development of gastric cancer. H.pylori infection can be served as an important clinical marker for evaluation of development of gastric cancer.