The effects of organic and inorganic sources on the growth of Anabaena syhaaerica HB 1017 are studied. The result shows that in organic carbon sources，the most effective concentrations of glucose and sucrose are 0. 5-1. 0 pg/mL and 5. 0 pg/mL respectively;while in the inorganic carbon soureces，the most effective concentrations of sodium carbonat and bicarbonat are 10. 0-15. 0 pg/mL and 10. Oug/mL respectively. The concentration of glucose or sucrose have no influence on the chlorophyll., but A. sphaerica HB 1017 bit a little more chlorophyll a when cultured in medium containing glucose than in containing suerose. Both sourcess carbonate of the four carbon and bicarbonate raise chlorophyll_a at the concentration of 5. 0 pg/mL. All sources can in the organic carbon sources enhance the nitrogen-fixing ability of A. sphaeria HB 1017，but sucrose has greater effect than glucose;while in the inorganic carbon sources，the effect of sodium carbonate is greater than that of sodium bicarbonate.