The invention provides a data processing method for transparent LCD; which computes the color saturation of each display pixel based on the grayscale values of the red, green and blue sub-pixels of each display pixel, and selects corresponding equation to compute the grayscale value of the transparent sub-pixel based on the color saturation. When in low color saturation, the invention increases the transmittance of the transparent sub-pixel; when in high color saturation, the invention lowers the transmittance of the transparent sub-pixel; and when the color saturation is in the middle range, the invention balances the transmittance of the transparent sub-pixel. As such, the invention realizes the real time adjustment of the transmittance of the transparent sub-pixel of the transparent LCD and improves the display effect of the transparent LCD.