Abstract: We selected the blue-green Spirulina maxima to reserch the photosynthetic oxygen-evolution and ultrastructure.Spirulina maxima was cultured in our laboratory.The results show:1)Spirulina maxima has higher capability of photosynthetic O₂-evolution;2)The thylokoids membrane,gas vacuoles,carboxysomes and phycobilisome,were prestened in cell.These photosynthetic apparatus and cell structure organelle were adapted with the role of photosynthetic oxygen-evolution.3)The thylokoids membrane regularly arranged and stacked in part regions of cytoplasm,and becomed a whole system of light energy conversion as chloroplast in higher plants.4)In evolution opinion,the existense type of thylokoid and special structure in Spirulina maxima showed part evidense:supporting the close similarity between photosynthetic appratus of blue-green algae and the chloroplast of eukarytes.The chloroplast of green algae and higher plant evolve from the photosynthetic appratus of prokaryotic blue-green algae.Spirulina maxima is one of representatives of evolutionary link between blue-green algae and higher plant.