In this paper, we developed a simple hydrothermal method to synthesize vertically aligned ZnO:Al nanorods (NRs) to fabricate a UV photodetector (PD) on a seed layer/glass substrate. The photo-to-dark current ratio of the ZnO:Al NR PD was approximately 1.4 x 103 under 1-V bias and UV light irradiation (380 nm). The calculated responsivity of the fabricated PD was 181 A W-1 , and the UV-to-visible rejection ratio of the PD at 1-V applied bias was 1.51 x 103. In addition, flicker noise dominated the noise of the ZnO:Al NR PD. The noise-equivalent power and normalized detectivity of the ZnO:Al NR PD were 1.17 x 10-11 W and 4.03 x 1012 cm Hz0.5 W-1 , respectively.