The Nano-ZnO material was synthesized by using the hydrothermal method. The structure, morphology and optical properties of Nano-ZnO material was studied by changing the concentration ratio of Zn(CH₃COO)₂•2H₂O and NaOH. The experimental results showed that, as the concentration ratio of Zn²⁺ and OH⁻ decreased gradually, the crystallinity of Nano-ZnO sample would increase gradually. The morphology of the sample firstly changed from sheet to rod-like, and finally changed from rod-like to sheet. It indicated that the concentration ratio of Zn²⁺ and OH⁻ was the main factor determining the morphology of Nano-ZnO. The optical property test results showed that, there appeared a distinct ultraviolet emission peak of Nano-ZnO near 380 nm; there appeared an extremely strong visible light emission band in the wavelength range of 450–650 nm; the luminescence intensity of Nano-ZnO would significantly increase with a decrease in the concentration ratio of Zn²⁺ and OH⁻; both the ultraviolet emission peak and the visible light emission band were blue-shifted.