So far, 21 species of brown algae have already been reported from Xisha Islands, Guangdong Province, China (Tseng,C.K. and Lu,B.R.1978; Fan,K.C，et al.1978).In the present paper, seven species of the marine brown algae are reported, namely，(1) Ectocarpus breviarticulatus J.Ag., (2) Giffordia mitchelae (Harvey) Hamel.,(3) Sphacelaria tribuloides Menegh.,(4) S.novae-hollandiae Sonder.,(5)* S.furcigera Kuetzing, (6) S.fusca (Hudson) C. Ag，(7) S.carolinensis Trono,. They are all recorded from Xisha Islands for the first time and two species (with asterisk) are recorded from China for the first time.These species are fully described on the basis of our own materials to facilitate better understanding of these seaweeds. The specimens studied were collected from Xisha Islands during 1957, 1958, 1975 and 1976.