In this study, C# programming language on the Visual Studio platform and a novel algorithm were used to develop software for the calculation and analysis of the oil film thickness distribution. The execution of the software is divided into file reading, conversion to grayscale values, inputting coordinates or drawing a line manually, and data acquisition. This software also provides the grid auxiliary function, the storage of the original image, the storage of the grayscale versus pixel graph, and the storage of data functions. After grayscale data are obtained from the above steps, they will be drawn into a line chart. The changes in bright and dark fringes can be clearly distinguished from the grayscale image, and the film thickness is calculated using the interference equation. In this study, we used an optical elastohydrodynamic lubrication (EHL) impact tester and the self-developed film thickness measurement software (FTMS) to measure the dimple film thickness occurring when a ball impacts a flat plate covered with a thin layer of oil for different operation parameters. Excellent agreement between the value determined with FTMS and that determined with the commercial software has been reported after a series of comprehensive experiments.