The present invention proposes a manufacturing method of a liquid crystal display panel. The method includes: injecting liquid crystal molecules having monomers into a liquid crystal box; detecting an alternating-current deflection voltage between a transparent electrode of an array substrate and a transparent electrode of a color filter substrate in connection areas of the liquid crystal display panel; applying the alternating-current deflection voltage between the transparent electrode of the array substrate and the transparent electrode of the color filter substrate when values of the alternating-current deflection voltage are all equal to a setting value; irradiating the liquid crystal display panel to form the polymer alignment films.