Abstract: Objective: To investigate the change of Th1 /Th2 cellular immune response in patients with gastric lesions associated with Helicobacter pylori(Hp) infection and its correlation with the genesis of gastric cancer. Methods: Enzyme linked immunosorbent assay was employed Objective: To determine the levels of serum -interferon (IFN-) and interleukin-4 (IL-4 ) in patients with chronic superficial gastritis(CSG),preneoplastic gastric diseases(PGD) and gastric cancer(GC). At the same time， immunohisObjective: Tochemisty staining was employed Objective: To determine the expression of IFN- and IL-4 in the gastric biopsies of the 3 groups. Results: The level of serum IL-4 in CSG with Hp infection was lower than that without Hp infection(P ＜ 0. 01) ; the level of serum IL-4 was elevated along with the progression of pathological changes in the cases of CSG，PGD and GC with Hp infection，but the difference was not significant among the three groups(P ＞ 0. 05),and the difference in the level of serum IFN- was not significant among the three groups， Objective: Too(P ＞ 0. 05). The immunohisObjective: Tochemisty staining showed high expression of IFN- in the inflammation biopsies with Hp infection(P ＜ 0. 05) ; and the expression of IL-4 was high in the gastric cancer biopsies with Hp infection(P ＜ 0. 05). Conclusions: Local Th1 /Th2 cellular immune response has correlation with the progression of pathological changes in patients with Hp infection，especially in patients with gastric cancer.