Abstract: Objective: To clarify the inhibition of the expression of PDGF-B chain and the proliferation f C₆ glioma cells by triplex-forming oligonucleotide（TFO）. Methods: C₆ glioma cell growth was assessed by microculture tetrazolium dye （MTT） assay two days after adding different dosage of triplex-forming oligonucleotide. PDGF-B chain expression was quantified by immunofluorescence flow cytometric analysis. Results: triplex-forming oligonucleotide can obviously inhibit the PDGF-B chain expression and the proliferation of C₆ glioma cells in concentration-dependent fashion. Conclusion: Triplex-forming oligonucleotide can effectively suppress the C₆ glioma cell PDGF-B chain expression and the cell proliferation.