Image sensing device and black level correction method thereof

The invention discloses an image sensing device and a black level correction method thereof. The image sensing device comprises a pixel array. The pixel array comprises a first non-photosensitive area, a second non-photosensitive area and an image pixel area. The black level correction method comprises the following steps: receiving a first analog signal, a second analog signal and a third analog signal from a first non-photosensitive area, a second non-photosensitive area and an image pixel area every other predetermined scanning period; respectively converting the first analog signal, the second analog signal and the third analog signal into a first digital signal, a second digital signal and a third digital signal by using an analog-to-digital converter of the image sensing device; and performing black scale correction processing on the third digital signal according to the first digital signal and the second digital signal to generate a black scale correction digital signal, wherein the black scale correc