Abstract: Under different light treatment and chlorophyll testing, seed of three onion varieties could be rapidly identified. There is a significantly different of seedling color betweent unpigmented and pigmented onion seedling by naked eye under black germination condition, the seedling color of red and yellow onion almost looks same, there are no significantly different of Chlorophyll contains. Pigmented onion seedling has significant high Chlorophyll contains than unpigmented under visible light germination condition, but it looks same by naked eye, no color different between each onion seedling.