The invention discloses a liquid crystal mixture with a giant electrothermal effect based on biaxial liquid crystal molecules. The biaxial liquid crystal molecules are added to a nematic liquid crystal mixture at the ratio; and the system comprises the following components in percentage by mass: 80%-95% of a nematic liquid crystal mixture with high dielectric anisotropy and 5%-20% of biaxial liquid crystal molecules. The preparation method comprises the following steps: evenly stirring the selected biaxial liquid crystal molecules and the nematic liquid crystal mixture with high dielectric anisotropy, so as to obtain the liquid crystal mixture with the giant electrothermal effect; and adding the biaxial liquid crystal molecules to the mixture, so as to play a role in induced orientation on mother liquid crystal molecules, thus the thermodynamic entropy change of the liquid crystal mixture under the electric field action is increased; the adiabatic temperature change is improved; and the maximal adiabatic temperature can reach 10.27 DEG C. The liquid crystal mixture has the advantages of good stability, low viscosity and fast electric field response.