Objective To explore the effect of β-catenin on proliferation and survive of U87 glioma cells after radiation. Methods To reduce the accumulation of β-catenin, U87 glioma cells were treated with 5 μmol/L IWR- 1-endo. CCK-8 and single colony formation assay were used to examine the proliferation and survival of U87 cells after radiation. And immunocytochemistry (ICC) was used to monitor the expressions of related proteins in the cells. Moreover, electron microscopy was used to observe the changes of microstructures of the cells. Results The expression of β-catenin decreased dramatically in the U87 cells after radiation treatment compared to the control group (P < 0.05). After radiation, the proliferation of the IWR-1-endo-treated cells and the plate colony-forming efficiency increased (P < 0.05). Conclusions Decreased accumulation of β-catenin might reduce the proliferation of glioma cells through inhibition of the Wnt/β-catenin signaling pathway, but it might cause radiation resistance of glioma cells by protecting the mitochondria of the cells.