The effects of temperature on spore release, growth and photosynthetic efficiency of Lithophyllum yessoense and Hildenbrandia rubra were examined. L. yessoense was collected at Galnam and H. rubra was collected at Gyeokpo, Korea. The experimental temperatures were different for spore release (10, 15, $20^{circ}C$), sporeling growth (10, 15, 20, 25, $30^{circ}C$) and photosynthetic efficiency (10, 15, 20, $25^{circ}C$). All other culture conditions were the same: 34 psu, 12:12 LD and $50{mu}mol$ photon $m^{-2}s^{-1}$. Spore liberation was maximal at $10^{circ}C$ for L. yessoense and at $20^{circ}C$ for H. rubra. After 14 days, the surface area of L. yessoense was 0.031 $mm^2$ at $25^{circ}C$ and for H. rubra was 0.032 $mm^2$ at $20^{circ}C$. Sporelings of L. yessoense were a dark-red color and grew in a round shape. In contrast, H. rubra was bright pink and changed from a round shape in the early growth stage to later become flabelliform. Photosynthetic efficiency was highest between $20-25^{circ}C$ in both species. In conclusion, L. yessoense and H. rubra display different physiological features based on the optimal temperatures for spore release and sporling growth.