The invention discloses an image processing method and device. The method comprises the following steps: setting an AD gain parameter, an AD offset parameter and a constant current source DC parameter in sequence; adjusting the constant current source GS parameter to acquire bright data and dark data; acquiring image data, and processing an image according to a preset correction formula, the bright data and the dark data; and outputting the corrected image data. According to the image processing method and device disclosed by the invention, the value of the dark data in the correction formula is increased to achieve the purpose of eliminating background data, and the dark data is acquired by properly increasing relatively short exposure duration; and a CIS image sensor collects the image data through the scheme, the background data can be completely eliminated after correction, and the consistency of the image data is relatively good.