Abstract: Objective To observe the effect of different concentrations of glucose and insulin on the secretion of TGF-β₁ in Colon26 tumor cells. Methods According to the concentrations of glucose and insulin in culture medium, cells were divided into 12 groups. After glucose and insulin were added into different groups, cells were cultured for 48h. In all experiments TGF-β₁ concentration in the supernatant were detected by ELISA. Results (1) In group D,the level of TGF-β₁ was higher significantly than group A(P<0.01). However no differences between group B and A, C and group A were detected(P>0.05).(2) In group E, F and G, compared with A, there was no statistical difference about the secretion of TGF-β1 in Colon26 tumor cells (P>0.05).(3) In group L, M and N, the levels of TGF-β₁ were higher significantly than A(P<0.01).However no differences between group H and A, K and A was detected(P>0.05). Conclusion (1)High concentration of glucose may up-regulate the secretion of TGF-β₁ in Colon26 tumor cells.(2) Different concentrations of insulin have no effect on the secretion of TGF-β₁ in these cells.