Objective To detect the expressions of two protein factors hypoxia-inducible factor (HIF)-1α and Helicobacter pylori (Hp) in gastric cancer in Mongolian and Han two nationalities respectively,and to explore the relationship of HIF-1α and Hp in the development of gastric cancer.Methods A modified Warthin-Starry (W-S) silver staining method was used to detect Hp infection in 27 Mongolian patients with gastric cancer and 30 Han patients with gastric cancer.Immunohistochemical (S-P) method and reverse transcription polymerase chain reaction (RT-PCR) method were used to detect protein and mRNA expressions of HIF-1α in cancer tissue,paracancerous tissue and normal tissue samples.The relationship of HIF-1α protein and Hp expression was analyzed between gastric carcinoma tissue samples of Mongolian patient group and Han patient group.Results Hp infection rates were 81.5％ (22/27) and 66.7％ (20/30) in Mongolian and Han patients with gastric cancer.The difference in infection rate was not statistically significant between two groups of patients (~=1.608,P ＞ 0.05).The positive expression levels of HIF-1α protein were 62.96％ (17/27) and 70.00％ (21/30) in gastric cancer tissue samples of Mongolian and Han groups.The relative expression levels of HIF-1α mRNA were 0.891 4±0.075 0 and 0.907 4±0.065 5.There was no significant difference in the HIF-1 α mRNA expression between the two nationalities.No positive expressions of HIF-1α protein and mRNA were found in paracancerous tissue and normal tissue samples.There was a positive correlation in the positive expression of HIF-1α protein and Hp infection in gastric cancer tissue samples of Mongolian and Han patient groups (r,=0.424 and 0.617,P ＜ 0.05).Conclusion HIF-1α and Hp are pathogenic factors of gastric cancer.Hp and HIF-1α may promote the occurrence of gastric cancer together.The pathogenic mechanism of HIF-1α and Hp in gastric cancer may be the same for Mongolian and Han patients.