Plasmonic enhancement is an effective method to improve the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). The size and amount of plasmon play key roles in plasmonic effect; however, the report on the relationship between morphology and processing of plasmon is rare. In this work, a series of Au nanoparticles (NPs) inlaid into TiO2 nanotube (NT) based photoanodes have been synthesized through tuning HAuCl4 solution concentration and irradiation time during the photoreduction process. Meanwhile, the optical and photoelectrical properties of these plasmonic DSSCs have also been verified. The results demonstrate that the optimized plasmonic DSSC (irradiation time: 5min, solution concentration: 0.5mM) showed a 19.0% improvement of PCE, compared to the reference DSSC without Au NPs. The improved PCE is mainly attributed to the enhanced photocurrent generated by surface plasmon resonance (SPR) effect of small sized Au NPs as well as light scattering effect of large sized particles. [GRAPHICS]