Aimed at the shortcoming of high cost and noise in mechanical paper counter, the paper counting algorithm based on gray value difference of paper was adopted and tested in order to resolve these issues from a visual way. After the image graying of neatly arranged paper, with the Gabor filter grayscale image edge enhancement, the gray pixel curve was obtained by using the gray value difference after gray projection. The thickness of a sheet of paper could be preliminarily judged based on the interval of peaks as the position of peak or valley could be accurately located after the exclusion of peak valley disturbance. Then paper counting was conducted according to the location markers. The counting results showed that this paper counting method could perform with simple operation, while the accuracy rate of paper counting achieved more than 97%.