To verify the feasibility of the high-salinity seawater pretreatment method and to ascertain the optimum conditions for production, the effect of high-salinity stress on the photosynthesis of was studied using methods from experimental ecology. In this study, branches of were incubated at five high salinity levels (40, 45, 50, 55, and 60 psu) for 30 min, with natural seawater (33 psu) as a control. Afterwards, these incubated branches of algae were transferred to natural seawater to recover for 12 h and 24 h, respectively. pH compensation point, chlorophyll fluorescence parameters, oxygenic photosynthesis, and the contents of photosynthetic pigments were measured at different salinity levels and recovery times. After algae were incubated at 40 psu for 30 min, the pH compensation point increased slightly, while RO and decreased significantly. When salinity was higher than 40 psu, the pH compensation point and (Ⅱ) decreased, while RO decreased with increasing salinity level above 40 psu. The Chl a/Car value was significantly different among the different salinity treatment levels (<0.01), while no significant difference was found between different incubation times within the same level of salinity. Significant changes in PE content (<0.01) were observed, especially at 45 and 55 psu. After 12 h recovery, the overall value of stressed algae was still significantly lower than of control algae ((Ⅱ) began to increase. After 24 h recovery, the photosynthetic indices of stressed algae including (Ⅱ), Chl a, Car, PE, PC, and Chl a/Car were close to fully recovered. This study indicated that the algae can adjust its photosynthetic characteristics under high-salinity stress, and as a result its photosynthetic parameters are able to return to a normal level after 24 h recovery. In conclusion, the pretreatment method is feasible, and exposure to salinity of 50-55 psu for 30 minutes is a suitable treatment condition.