GBM, a grade IV astrocytoma that originates in the brain, is the most aggressive and common primary neoplasm . Owing to short median survival time (around 12–15 months) and poor prognosis, elucidation of molecular mechanisms in GBM is urgently needed . Although it was reported that CBX7 was downregulated and inhibited cell migration in glioma cells, the effect of CBX7 on cell cycle disregulation, another typical characteristic of GBM, is still unclear. In this study, we tested the relationship among CBX7 mRNA level, tumor grade and poor prognosis in CGGA, TCGA, REMBRANDT and GSE16011 datasets. We found that CBX7 possessed prognostic value in glioma patients. Then bioinformatics analysis indicated that CBX7 played a tumor suppressor role in glioma progression, especially in cell cycle control. CBX7 overexpression impaired the proliferation, migration and invasion of GBM cells; downregulation of CBX7 had the opposite effects. Furthermore, CBX7 inhibited G1/S phase transition via binding and silencing CCNE1 promoter mediated by the recruitment of HDAC2. Finally, CBX7 attenuated tumor growth in a xenografted model. Taken together, CBX7 participates in G1/S checkpoint control and is a novel prognostic marker in glioma patients.