Abstract: The materials used in this experiment were the epee cut 3---9 cm long from the branches of fronds of Caid2um. They were cultivated under different temperatures and water depths in the sea. The experiment were carried out from March 1979 to Marsh 1980 in Tandao Bay (faingdao)，W eihai Harbour and Lungkau Bay of Shang- dung in north China. The results are as follawai.Theolmuzxtemperature of growth of the algae is at 24-280C. The favorable growth temperature ranges from 80C above. The low limit temperature for growth pro- bably is 00C.，fV bile the high hmzt remains unknown.2.Althov this algae is genera3ly known for living under tidal But it grows rapidly in water depth of d.3 meter, in the agperiment, and increasing the depth sla-zvering the growth of the algae.3.After 5----1a ciasys, soma duds of rhizoid grew up at the end parts of the main Faranches at the temperature of 2d-280G. Hence, it is considered as the optimum tem- perature for the growth of rhixoids.