The cultivation of purple laver in Guangdong province was started in September,1966. The conchocelis of Porphyra haitanensis T. J. Chang et B. F. Zheng wereintroduced from Fujian province and their thallus were cultivated following spore-collecting. Guangdong province is situated in the subtropics region, the harvest scasonof P. haitanensis is very short and the yield is low. Since a well adaptable species isnecessary to select several species of purple lavers from different regions of Guangdongcoast were collected and cultivated in January, 1974. During the period of cultivationtill the spring of 1977 the experiment had shown that P. guangdongensis adapted tohigher temperature better than P. haitanensis. During Novermber, 1978 to January, 1979 some measurements of respirationwere made and the results had shown that the rates of O₂consumption, CO₂releasedand the respiratory quotients of P. haitanensis were much higher than those of P.guangdongensis at the same temperature. Especially at 25℃ the differences of the ratesof O₂consumption and CO₂releasing for both species were very significant(ρ0.001). During December, 1979 to January, 1980 the rates of photosynthesis for bothspecies under different temperature were also measured. The experiment showed thatof P. guangdongensis at 30℃ (19.53μl O₂/mg d. w./h)and P. haitanensis at 23℃ (20μlO₂/mg d. w./h.) the rate of photosynthesis reached to maximum. While the raise ofwater temperature the rates of photosynthesis decreased. The ration of photosynthesis and respiration of P. guangdongensis were higherthan that of P. haitanensis within the temperature range of 25-33℃. The data fromindoor experiments agreed with the results of outdoor cultivation. P. guangdongensis is recognized to be better adapted to higher temperature and having faster growththan P. haitanensis