Abstract: Four experiments were conducted to study the effect of sea salinity on the attachment, development and survival of Gloiopeltis furcata spore. In the first experiment, the fertile thalli of G.furcata were incubated at different salinities (16.0~38.5). In the second experiment, G.furcata spores were incubated at different salinities (13.5~41.0). In the third experiment, the germinating spores of 24 h and 48 h were incubated at different salinities (6.0~66.0). In the fourth experiment, the germinating spores of 24 h and 48 h were incubated in freshwater for different hours (2 h, 4 h, 6 h, 8 h). The results show that the spores released at salinity of 23.5~36.0 could normally adhere and develop; the appropriate salinity for attachment, development and survival of G.furcata spore is 31.0~36.0; there was no significant difference in the survival of the germinating spores (24 h) at salinity of 31.0~56.0, but there is difference in the survival of the germinating spores (24 h) incubated in freshwater for different hours; there is no significant difference in the survival of the germinating spores (48 h) at salinity of 16.0~61.0 or those incubated in freshwater for 2 h.