In this article, new p-DSSC electrodes are fabricated using NiO hollow spheres (HSs) prepared through a facial one-step hydrothermal process. The current-voltage (J-V) curve indicates that p-DSSCs fabricated using triple-shell NiO HS have excellent photoelectrochemical performance, with a photoelectrical efficiency of 1.79%. The UV-vis diffused reflectance spectra indicate that the triple-shell NiO HS, with its unique structure, has superior light reflection, scattering ability and large surface area with more inner cavities, which helps harvest more light. Electrochemical impedance spectroscopy (EIS) further confirms that triple-shell NiO HS shows fast dye regeneration, improved hole transport and suppressed recombination. The research work of unique NiO HS is important for the selection of efficient photocathode materials for p-DSSCs.