Abstract: Impact of different environmental factors on growth and polysaccharides characteristics of Nostoc commune Vauch from Shenzhen seashore were analysed by orthogonal experiment. The results showed that under the appropriate conditions of temperature,illumination intensity,inorganic salt and UV-B treatment,the relative growth rate（RGR）,the content and the anti-oxidant capacity of extracellular polysaccharides were significantly stimulated. The culture conditions were that 30 ℃ temperature,0 mmol/L NaCl,100 μmol/（m²·s） illumination intensity and 10 kJ/（m²·d） UV-B treatment,the relative growth rate was the highest. When the conditions were that 35 ℃ temperature,NaCl concentration at 40 mmol/L,illumination intensity at 200 μmol/（m²·s） and UV-B treatment at 20 kJ/（m²·d）,the extracellular po1ysaccharides concentration were the highest. The most significant factor for the relative growth rate（RGR） and EPSs were temperature and UV-B treatment,respectively.

Key words: Nostoc commune Vauch, growth, extracellular polysaccharides, environmental factors