A method of grayscale calibration of subpixels of liquid crystal panels during imaging includes: obtaining a first brightness value when the subpixel of the i-th color has a maximum grayscale; calculating a second brightness value of each grayscale(j); obtaining a third brightness value of each grayscale(r) of the main subpixel area and a fourth brightness value of each grayscale (s) of the secondary subpixel area of under the direct view condition; determining value combinations for the main and the secondary subpixel area of the subpixel having the grayscale (j) and satisfying a predetermined criteria; calculating total color differences of the grayscale images respectively for the direct and a squint view condition when the value combination being applied; determining the value combination of the minimum total color difference as the value combination applied for the subpixel. With such configuration, the color shift of the liquid crystal panel may be reduced.