Abstract: The most suitable growth conditions of photosynthetic bacteria PSB-B were studied for replication.On the basis of single factor experiment, the method of response surface analysis with 3 factors and 5 levels including temperature, pH and NaCl concentration were adopted through design - expert software with central composite rotatable design analyzing data. The most suitable growth conditions of photosynthetic bacteria PSB - B were determined as following: temperature 28℃, pH value 6.80 and NaCl concentration 0.25g /100mL.Under these conditions, OD of strain PSB - B was 1.446. The results showed that the experimental value was comparable to model prediction and the method was practical.