The invention discloses a data demodulation method and device based on visible light communication and is to solve the problem that a conventional data demodulation method based on visible light communication is low in accuracy in the prior art. The method comprises the following steps: carrying out gray processing on an image corresponding to an obtained visible light signal; obtaining a gray value of each pixel point in the image; according to the gray value of each pixel point in the image, determining a first grey value corresponding to each line of pixels of the image, wherein the first grey value is the sum of the gray values of all pixel points in the line of pixels; and according to the first grey value corresponding to each line of pixels of the image, determining data in a binary format corresponding to the image.