The experimental system is built with the Michelson interferometer as the core equipment，and the debugging scheme of double light source optical interference fringes is proposed． The image processing technology based on Python is introduced to analyze the coincidence degree between the reference pattern and the adjustment pattern to judge the adjustment boundary，which realizes the accurate measurement of film thickness． Experiments were conducted using soap film as a sample，and the results showed that the experimental scheme had good operability and repeatability，improved measurement accuracy compared to visual estimation algorithms，and provided a solution for non-destructive measurement of liquid film thickness．It can also be introduced into university physics experiments to enhance students’research and innovation

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