The TiO2 based dye-sensitized solar cells doped with different sizes of ZnO nanorods were fabricated and studied by photoelectrochemical measurements. The results show that the energy conversion efficiency of the dye-sensitized solar cells after the addition of ZnO nanorods(1%, mass fraction) was increased by 6%—20% in comparison with that without ZnO nanorods. The effect of different sizes of ZnO nanorods on the electronic transportation properties was studied in the composite semiconductor film by means of transient photovoltage technology(TPV). The result indicates that the electron diffusing velocity in N3-sensitized TiO2/ZnO film electrode was about 1—3 order of magnitude faster than that in TiO2 electrode. The experimental results indicate that the TiO2/ZnO electrode can improve the electron transport, decrease the recombination, enhance Voc, and increase efficiency of energy conversion.