Based on the prineiple of total relleetion ,this study introduees an inventive method for measuringliquid concentration.By employing a specifically designed container to hold the test solution and utilizing amobile phone to eapture the total relleetion of light on the liquid's surface, the criical angle was preciselyobtained.Through this eritical angle and relevant equations , we derived the refractive index and concentrationvalue of the transparent liquid.This experiment not only employs intuitive optical techniques but also integratesmobile soltware, signilieanlly redueing measurement errors, equipment costs and faeilitates operation.F'urthermore ,the broadened seope of this experimental design approach brings optical experiments eloser todaily life,facilitating their widespread adoption and promotion.