Abstract: Grateloupia livida is a kind of commercial and scientific red alga with potential value in nutraceuticals and pharmaceuticals. We investigate the early development of G.livida at different temperatures (15 ℃, 20 ℃, 25 ℃ and 30 ℃) and light intensities (500 lx, 2 500 lx, 5 000 lx and 10 000 lx). The results show that the optimal conditions for the development of carpospores are temperature 25 ℃ and illumination 5 000 lx. The discoid crusts form were firstly at 25~30 ℃ and lastly at 15 ℃. Seedings cultured from discoid crusts were firstly observed at 25 ℃, then at 20 ℃, 15 ℃ and 30 ℃. The discoid crusts form firstly at 5 000~10 000 lx and then at 2 500 lx. In conclusion, high light intensity significantly accelerates the growth and development of discoid crusts. Low light intensity of 500 lx retards the growth and development of discoid crusts of G.livida.