The effects of illumination on growth of Anabaena sp. IB02 and hTNF-alpha expression were studied. Photosynthetic activity, PS I and PS II activity of Anabaena sp. IB02 were assayed. Illumination enhanced the growth of Anabaena sp. IB02 and hTNF-a expression. Some relations were observed between hTNF-alpha expression and ture photosynthesis activity, PS I, PS II activity of Anabaena sp. IB02. Significant differences of the photosynthetic activity of host were detected simultaneously when hTNF-a expressed: the respiration rate increased (-68%), the light saturation point descended (+66%), all these suggested that the metabolic charge of host were increased and grow faster than wild type under low illumination.