To investigate the mechanisms of nordihydroguaiaretic acid (NDGA) on cell proliferation inhibition of human glioma cell line SHG-44, the techniques of cell culture, immunohisto-chemisty, in situ hybridization and FCM are employed in this experiment. The results are obtained that ① SHG-44 cell proliferation was blocked in G1→S phase by NDGA, ② The expression of P16 gene in cells increased and cyclin D1, CDK4 gene decreased after treatment of NDGA. These data suggest that effect of NDGA on cell proliferation inhibition of SHG-44 is probably completed by regulating the activity of CDK4.