The theory of three primary colors is one of the principles of color-conversion display devices, and the experiment of color-conversion is a common experiment showing the principle of three primary colors in thephysical experiment system. By combination the experimental content with daily life, it is effective to improvethe experimental teaching effect stimulate students’ learing interest. The students can use their own mobilephone as the experimental instrument for the observation of sub-pixel distribution of OLED sereen in the color-conversion experiment, which can not only complete the experiment but also mobilize students’ enthusiasm for exploration and achieve good teaching elfect. In this study, the designed experiment in this study does not needadditional light souree and color-converter compared with the current experiment. The designed experiment greatly reduces the cost and has good promotion significance.