TiO 2 nanoparticles (NPs) were prepared by cathode glow discharge electrolysis in sodium fluoride solution, in which cetyltrimethyl ammonium bromide (CTAB) acted as a stabilizer, and a Ti foil and a Pt needlepoint served as the anode and the cathode, respectively. The structure, component, and morphology of TiO 2 NPs were characterized. A possible preparation mechanism was proposed. In addition, the photocatalytic performance of TiO 2 NPs was assessed through the degradation of methylene blue (MB). The results showed that TiO 2 NPs with 12.7 nm particle size could be prepared at 500 V discharge voltage. CTAB, as a stabilizer, can diminish the agglomeration. The photocatalytic property of TiO 2 NPs for the degradation of MB with 0.15% CTAB is markedly superior to that of TiO 2 NPs without adding CTAB and commercial TiO 2 NPs (P25). K E Y W O R D S cathode glow discharge electrolysis (CGDE), nanoparticles (NPs), photocatalytic degradation, plasma, titanium dioxide (TiO 2 )