1. A method of adjusting a displaying state of a display apparatus, comprising: determining a reference color temperature and a reference Δu′v′; determining setting color temperatures corresponding to gradations of a gray level according to the reference color temperature to make color temperature differences between adjacent gradations of the gray level be within a predetermined color temperature range; measuring coordinates according to the gradations within a gray area formed by the gray level displayable in the display apparatus on a predetermined color coordinate system corresponding to the reference Δu′v′ and the setting color temperatures corresponding to the gradations; and setting the coordinates corresponding to the gradations measured about each gradation of the gray level of the display apparatus.