Under the 45°/0° illumination observation conditions of various light sources, an evaluation method and measuring device are developed to measure the flash effect of metallic coatings. Based on different color distributions and sparkle grades, 39 metallic paints are selected to create the sample database. Multispectral images of the collected samples are corrected to meet the visual response of the observer under different light sources. The sparkle points and background are separated by setting the threshold related to the images. An algorithm for the sparkle area, intensity, and grade is developed by calibrating the test data of BYKmac. The correlation between the sparkle grade measured by experimental setup and visual evaluation data is further evaluated under light sources D65 and A. Experimental results show that the correlation coefficient between the experimental device and visual data are 0.848 and 0.851 under light sources D65 and A, respectively. Moreover, the measurement effect of the experimental device is better than that of the existing measurement equipment.