A mixed liquid crystal was firstly prepared with liquid crystals 4-Cyano-4'-pentylbiphenyl (5CB) and 4-[trans-4-[(E)-1-propenyl] cyclohexyl] benzonitrile in a ratio of 5∶1 as raw material. Then the plain liquid crystal 5CB and the mixed liquid crystal were compounded with the pretreated carbon nanotubes (CNTS) respectively, which were characterized in terms of their photoelectric and dielectric properties. The results show that the addition of CNTS affects the threshold voltage and dielectric anisotropy of the liquid crystal systems, as a result, the dielectric anisotropy increases by 4.671%, and the flexural elastic constant also increases; The addition of CNTS also affects the response time and viscosity coefficient of the liquid crystal systems, while the viscosity coefficient decreases by 25.131%. The experimental results also show that the dielectric anisotropy of the mixed liquid crystal is higher than that of the plain liquid crystal 5CB, while the decrease of response time and viscosity is more obvious. The greater advantage of the mixed liquid crystal is that the doping of carbon nanotubes can result in significant improvement in the physical parameters and display performance of the composite system. At the same time, the theoretical research results show that the binding energies of carbon nanotubes and liquid crystal molecules are between those of liquid crystal molecule pairs and carbon nanotube pairs respectively, as a result, dipole moments may be induced by the asymmetric charge distribution of the liquid crystal molecules adsorbed on carbon nanotubes, which can well interpretate the fact that the doped carbon nanotubes can improve the dielectric anisotropy of liquid crystal materials, while reduce the response time.