Tree-like branched TiO2 nanorod arrays (BTNR) are prepared on FTO substrate. Ag NPs with size gradient distribution on BTNR are achieved via photo-reduction process. Ag NPs promote light absorption and scattering in BTNR/Ag photoanodes. Ag/TiO2 heterostructure promotes charges separation in DSSCs. BTNR/Ag enhances the conversion efficiency by 51.3% compared with BTNR.