Gastric cancer is a malignant tumor with the highest incidence and mortality rate and low 5-year survival rate in China. Treatment of gastric cancer is mainly surgery combined with radiation and chemotherapy. Due to the inconspicuous early symptoms of gastric cancer and the limited sensitivity and specificity of the current traditional tumor markers it is difficult to diagnose patients with early gastric cancer in China. Therefore the diagnostic pathways of early gastric cancer the targets of gastric cancer treatment and effective prognostic assessment methods have been major concerns. In recent years key enzymes in the energy metabolism of tumor cells have received more attention. Pyruvate kinase M2 PKM2 a key enzyme in the glycolytic pathway is abnormally expressed in tumor tissues serum and other body fluids and is involved not only in the nutrient metabolism of tumor cells but also in mitogenic activation. It is not only involved in the transcription of MAPK but also related to phosphatidylinositol-3-kinase PI3K / protein kinase B/ the mammalian target of tapamycin mTOR PI3K/ Akt / mTOR signaling pathway and NF-κB/ miR-148a / 152 feedback loop and other processes and through the above responses promote the proliferation invasion metastasis and vascular tumorigenesis of gastric cancer cells and inhibit apoptosis of gastric cancer cells. Recent researches have shown that PKM2 can be used for early diagnosis treatment and prognosis assessment of gastric cancer. This study reviews researches about early diagnosis treatment and prognosis assessment of PKM2 in gastric cancer in recent years which provide insight for improving the sensitivity and specificity of diagnosis developing new treatment strategies and prognosis assessment.