In this research, we analyz the effect of the intensity of the light spectrum on the color of red and green on germination and photosynthesis of green beans (Vigna radiata L.). The purpose of our research is to know the most effective wavelength for photosynthesis and comparison of effect of red and green light spectrum on germination. First, tools and materials to be prepared are cardboard, plastic cup, cutter, scissors, ruler, green bean seeds, double tape, red mica, green mica, cotton, and water. Second , create a research framework. Third, analysis of data obtained from observation of root lenght size, number of leaves, stem diameter and height of plant. The data indicate that the germination in the red color spectrum is faster than in the green color spectrum because the red color spectrum has the most effective wavelength for chlorophyll to perform photosynthesis and growth than the green color spectrum.