|| The barrier layer of closed-ended TiO2 nanotube arrays (C-TNTAs) was etched by ion milling method and Au nanoparticles (Au NPs) were incorporated into open-ended TNTAs by an electrodeposition method. Then applied to the dye-sensitized solar cell (DSSC) to improve energy conversion efficiency (ECE). Compared to without Au NPs, the ECE of DSSC with Au NPs into C-TNTAs is increased from 5.502% to 6.116%, an enhancement of 11.16% because of the plasmonic and charging effects of Au NPs. However, the ECE of DSSC based on C-TNTAs incorporated with many Au NPs decreased from 6.116% to 5.336% because aggregation of the Au NPs led to decrease open-circuit voltage (Voc) and fill factor (FF). For better ECE, the barrier layer of Au NPs-embedded C-TNTAs with efficiency of 6.116% was removed using ion milling method, with interval of 0, 30, 60, 90min. After the barrier layer was completely removed, the ECE was achieved at 7.120% because electron transport and electrolyte diffusion were increased.