The invention provides a liquid crystal display panel and a preparation method thereof. The preparation method comprises the steps that a first substrate is coated with a frame sealing adhesive, and amixture prepared from a liquid crystal material, a polymerization monomer, a photoinitiator and an ultraviolet absorption dye is added on a second substrate dropwise; the first substrate and the second substrate are oppositely combined, the first substrate, the second substrate and the frame sealing adhesive form a closed cavity, and the closed cavity comprises a display region and a peripheral region, the frame sealing adhesive is cured, and the polymerization monomer is cured inside the peripheral region through a photomask to form a plurality of supporting structures. The polymerization monomer is added into the liquid crystal material, and ultraviolet light irradiates the peripheral region inside the box after opposite combination to form the polymer supporting structure, so that thestrength of the panel is enhanced, the box thickness uniformity is improved, light leakage, yellowing and other poor phenomena are reduced, the display quality is improved, and the display product opening rate and transmittance can be improved to a certain degree.