The invention provides a production method of a liquid crystal substrate. An organic insulation PLN (planarization) layer is formed on a color filter with a halftone mask technology, the height of the organic insulation PLN layer correspondingly located on a blue pixel region is enabled to be larger than the height of the organic insulation PLN layer correspondingly located on a red pixel region and the height of the organic insulation PLN layer correspondingly located on a green pixel region, so that display Mura of a large-sized high-resolution liquid crystal display device can be improved effectively, stray capacitance can be reduced, charging efficiency can be increased, normal cell gap parameter of the liquid crystal display device can be maintained, the problems of display chromatic aberration and reduced transmittance are solved effectively, and the optical quality of the liquid crystal display device is guaranteed.