Many parameters can be adjusted in light interference and diffraction phenomena which have rich phenomena．In order to better understand the relevant optical phenomena，visual analysis based on computer language is a very effective research method．Taking Yang’s double-slit interference and Fraunhofer single-slit diffraction experiment as examples，the relevant experimental phenomena are simulated by Python language， and then the experimental phenomena under different incident wavelength，different double-slit spacing，and different single-slit sizes are analyzed．The results show that the Python language has the advantages of intuitive image，simple operation，flexible and adjustable parameters，which provides useful support for the learning of relevant optical knowledge．