Abstract: A new model is established to measure visibility by using digital cameras and improves the agility and the measuring range of Digital Photography Camera System for measuring visibility. The following work is done: 1) An object-observation point model, which is appropriate for using cameras to measure visibility, is built based on Koschmieder Formula and LambertBeer Law and it eliminates the physical quantities that cannot be measured by cameras accurately, such as the background diffused light, the sky background light in the direction of an object and the object reflex.2) The following Error analyses are done: The error caused by inadequate resolution of the camera lens, dark current, deviation of camera parameter’s (exposure time, aperture) actual value and show value and nonlinear photoelectric response is diminished by finding the relationship between grayscale per pixel and luminance and some factors such as the properties of the object surface, the intervals of object and observation point are restricted. 3) A certain number of visibility records are obtained by utilizing, the model established above. Correlation coefficient is 99% the accuracy’s 17%. The result proves the feasibility of using camera to measure visibility preliminary.