Abstract: Objective To investigate the expression of M2-pyruvate kinase （PKM2） in gastric cancer and analyze its relationship with clinicopathological characteristics and prognosis of gastric cancer. Methods 202 paired of gastric cancer and corresponding adjacent tissues were evaluated by tissue microarray and immunohistochemistry for PKM2 expression. The relationship between the expressions of PKM2 in tumor tissues with clinicopathological characteristics and prognosis was analyzed. Results The overall positive expression rate of PKM2 in tumor tissues was 62.4％ （126／202）， higher than 14.4％ （29／202） of corresponding adjacent tissues with significant difference （P＜0.05）. The PKM2 expression is related with T stage， N stage and TNM stage （P＜0.05）， but not with age， gender， tumor size and degree of differentiation （P＞0.05）. The medium overall survival of PKM2-positive patients was 42.9 months， shorter than 78.4 months of the PKM2-negative patients （χ2=23.119， P＜0.001）， and the positive expression of PKM2 is one of the independent prognostic factors for gastric cancer. Conclusion Our results showed that PKM2 expression significantly increased with the progression of gastric cancer， implying the importance of PKM2 as a potential biomarker in cancer diagnosis and treatment.