The titanium dioxide (TiO2) nanoparticle (NP) structure has higher surface area and dye loading value to increase photon absorption while the nanotube (NT) can suppress the random walk phenomena to enhance carrier collection. In this work, hydrothermal method was utilized to infiltrate the TiO2 nanotube array by TiO2 nanoparticles with the aim of combining the advantages of both nanostructures to improve dye sensitized solar cells (DSSCs) efficiency. Structure morphology, device performance, and electrochemical properties were investigated. SEM observation confirmed that around 10 nm TiO2 nanoparticles uniformly covered the NT wall. TiO2 NT samples at three different lengths: 8 μm, 13 μm and 20 μm, decorated with different amount of nanoparticles were studied to optimize the structure for light absorption and electron transport to achieve high solar conversion efficiency. Electrochemical impedance spectroscopy (EIS) was also employed to investigate the cells’ parameters: electron lifetime (τ), diffusion length (Ln) et al, to gain insight on the device performance. The incident photon conversion efficiency (IPCE) was also reported.