Abstract:【Objective】To investigate the expression and clinical significance of granulocyte macrophage colony stimulating factor (GM-CSF) in colon cancer tissues. 【Methods】The expression of GM-CSF protein in colon cancer tissues and adjacent normal tissues collected from 68 patients with colon cancer in our hospital was detected by immunohistochemical staining, and its correlation with clinicopathological features was also determined. Then Kplan-Meier method was used to analyze the relationship between GM-CSF protein expression level and prognosis of colon cancer patients. 【Results】The expression level of GM-CSF protein in colon cancer tissues was significantly higher than that in adjacent normal tissues, and the difference was significant (P<0.05); there was no significant difference in the expression level of GM-CSF in the cancer tissues of patients with different gender, age, tumor location and histological grade (P>0.05); the expression of GM-CSF in the cancer tissues of patients with different tumor diameter, Dukes stage and lymph node metastasis was different The overall survival (OS) and progression free survival (PFS) of patients with positive expression of GM-CSF were significantly higher than those of patients with negative expression of GM-CSF (P<0.05).【Conclusion】GM-CSF is highly expressed in colon cancer, and its expression is correlated with lymph node metastasis and prognosis of patients with colon cancer. Detection of GM-CSF is helpful to understand the occurrence and progress of colon cancer, and provide reference for individualized treatment and prognosis judgment of colon cancer.