In the atmospheric visibility observation, most of the related research focus on daytime observation, while the researches on nighttime observation are rare, and the research on the continuous observation of day and night are rarely reported. At present, there is no automatic atmospheric visibility observation instrument developed by the definition of visibility at home and abroad. In order to solve this problem, based on CCD digital camera technology, the principle of artificial observation optics is simulated, and a method of continuous observation of atmospheric visibility is proposed. This method is based on the visibility calculation formula of the target. It modifies the system parameters in the day and night mode, which can effectively eliminate the observation error caused by the external environmental factors and the internal factors of the camera system. In order to verify the effectiveness of the algorithm, three sets of principle prototypes based on the method are built for different situations such as sky occlusion, semi occlusion and open space (different situations will affect the brightness of the observation environment, to test the system’s resistance to stray light and adaptability to different environments). They are using the built digital photography visibility system (DPVS) to observe the actual atmospheric visibility at a minute level in the Beijing area. Observation experiments show that the observation system based on this method has a wide observation range and can effectively adapt to all kinds of complex weather conditions. It has a good observation effect in different weather conditions such as rain, snow and haze, and the DPVS system can respond quickly and correctly no matter the visibility changes rapidly or slowly. Through the comparative analysis of the observation results of DPVS, scatterometer and transmission instrument, it is found that there is a high correlation between DPVS and the observation results of the former two instruments: 0.973 1, and the observation performance is similar, with the average relative error of -1.54% and the root mean relative square error of 8.82%. The maximum relative error of this algorithm is -14.11%. According to the World Meteorological Organization (WMO) MOR, if the maximum relative error of the visibility meter is less than 20% within the full range, it is considered a standard visibility meter and can be used in actual observation. The DPVS system based on this algorithm meets the observation standard and can be practical. Moreover, the observation cost of the DPVS system is much lower than that of the scatterometer and transmission instrument, so it has a good prospect and application value.