The properties such as cell gap, pretilt angle and rubbing direction in the multi domain PS(polymer stabilized)-VA cell were measured by a optical method. It has been impossible to measure the pretilt angle in sub micrometer area because liquid crystals in each area of the 4-domain PS-VA cell have different pretilt angle in the other direction. We could get the data using the optical measurement system merged microscope. Many failure muras caused during the liquid crystals process is analyzed successfully through the measurements. It is also very powerful tool to measure the cell gap below the protrusion in the pixel.