Hierarchical nanostructure of TiO2 nanoparticles/nanorod arrays (TiO2 NPs/NRs) is synthesized and applied in dye-sensitized solar cells (DSSCs) comparing with the TiO2 nanorod (TiO2 NR) arrays and the TiO2 nanoparticles (TiO2 NPs). The TiO2 NP/NR surface morphology is revealed by X-ray diffraction, field emission scanning, and transmission electron microscopy. The power conversion efficiency of NP/NR-based DSSCs (length 3 μm) is improved to 3.47%, which is 2.2 times higher than the NR-based DSSCs (length 3 μm), and rivals the NP-based DSSC (length 5 μm). The high photovoltaic performance was attributed to that the TiO2 NP/NR photoanode has large surface area and exhibits excellent light scattering, allowing for fast interfacial charge transfer and less charge recombination, which are characterized using the UV-vis absorbance spectra, Brunauer–Emmett–Teller (BET) surface area, electrochemical impedance spectroscopy (EIS) measurements, and photoluminescence (PL) spectroscopy. However, further work is needed to overcome the limitations of TiO2 NP/NR and improve the performance of TiO2 NP/NR-based DSSC.