Abstract: We studied the effects of different temperatures, salinities and light intensities on the growth and physical components of Porphyra crispata, and the results show that the suitable temperature and salinity for P. crispata growth were 17~23 ℃ and 25~35 with 17~20 ℃ and 30~35 as the optimum growth temperature and salinity, respectively. The thallus was inhibited and rotted when the temperature was above 23 ℃ or the salinity was above 35 or below 15, which indicates that the thallus has stronger resistance to lower temperature and higher salinity than to higher temperature and lower salinity. In addition, the thallus grew quickly under light intensity of 4 000~7 500 lx, so the photosynthesis of thallus reduced under low light intensity, while the metabolism, growth rate and glossiness were affected negatively under high light intensity.