Abstract: Grateloupia livida is a kind of commercial and scientific red alga with potential value in nutraceuticals and pharmaceuticals. We investigated the early development of G.livida at different temperature (15 ℃, 20 ℃, 25 ℃ and 30 ℃) andlight intensity (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.Thediscoid crusts formed firstly at 25~30 ℃ and lastly at 15 ℃. Seedings cultured from discoid crusts were firstly observed at 25 ℃, then at the temperature of 20 ℃, 15 ℃ and 30 ℃.The discoid crusts formed 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.