Abstract: Objective To study the relationship between the expressions of JAK1, p-STAT3 and bcl-2 and the tumorigenesis and development of human gastric cancer. Methods Immunohistochemical methods are used to detect the expressions of JAK1, p-STAT3 and bcl-2 in 60 gastric cancer tissues and 60 gastroscopy tissues. Results (1)The positive ratio of JAK1, p-STAT3 and bcl-2 expression were different in different tissues: gastric cancer ＞ atypical hyperplasia and adjacent mucosa＞ chronic atrophic gastrtis with intestinal metaplasia ＞superficial gastritis (P<0.05); (2)In gastric cancer the positive intensities of JAK1, p-STAT3 and bcl-2 expression were associated with differentiations, depth of tumor invasion, lymph node metastasis, distant metastasis and clinical stages (P<0.05); (3)The expressions of these three proteins were positive correlation (P<0.05). Conclusion The JAK1, p-STAT3 and bcl-2 were overexpressed in gastric cancer tissues compared with normal gastric tissues and related to its oncogenesis, invasion, metastasis and clinical stages closely.