The attenuation property of 1.06 μm laser radiation in water fog was investigated experimentally. The attenuation of 1.06 μm laser radiation in water fog was measured at different meteorological optical range(MOR). Based on experimental data, the equivalent ″MOR″ of 1.06 μm laser radiation was calculated. The extinction coefficient of 1.06 μm laser radiation in water fog at different MOR was calculated based on empirical equation and experiment data, respectively. The comparison of the result shows the empirical extinction coefficient has significant deviation with experiment result, especially at low MOR. A new equation was derived for calculating the extinction coefficient of 1.06 μm laser radiation in water fog based on MOR value, which is of great importance in evaluating the attenuation properties of near infrared laser radiation in water fog.