The size of the driving voltage is seen as a important index to choose the liquid crystal display device, it is related to the manufacturing costs, energy consumption, safety and practicality. At present, to meet a series of requirements of liquid crystal display such as lower driving voltage, faster response, more vivid color, better picture, saving energy and better animation, the researchers are focusing more on the liquid crystal / nanomaterial composites. When nanomaterials were doped into liquid crystals, it would be not only destroy the original structure of the liquid crystal, but also integrate its own unique properties into the liquid crystal, thereby improving the performance of liquid crystal. It was found that the semiconducting nanomaterials could produce the polarization electric field without polarization fatigue under electric field, leading to the enhancement of the electric-optical properties of liquid crystals. In our study, Cu2O semiconductor nanoparticles were added into a semctic liquid crystal, 8CB, and the effect on electric-optical properties of liquid crystal was studied. Cu2O nanoparticles have a large positive charge, which enhancing the interaction with the liquid crystal. And the electric field of the liquid crystal molecules around nanoparticles would speed the switching of molecular of liquid crystals, leading to a reduce of the threshold voltages of liquid crystal and further improving the electric-optical properties of liquid crystal.