Abstract: Prokaryotic cytoskeletal protein FtsZ, a microtubule homolog, assembles into a compact circular structure at the mid-cell and plays an important role in cytokinesis. To explore the function of FtsZ in Spirulina platensis morphogenesis, we cloned the ftsZ gene from S.platensis and constructed its fusion tag of GFP expression plasmid pGFP-FtsZ. The recombined expression vector was transformed to Escherichia coli BL21. Western blot analysis showed that the GFP-FtsZ fusion gene was successfully expressed in the transformant. The transformed bacteria that expressed the GFP-FtsZ protein changed from normal short-rod shapes and formed long filaments. The length of the filamentation cells was proportional to the expression amount of FtsZ in cells. Regular-dot distribution of the GFP-FtsZ fusion protein in transformed bacteria was observed by fluorescent light microscopy. The data demonstrated that FtsZ was a highly conserved functional protein. The FtsZ of S.platensis assembled the complete cytokinesis apparatus and formed a Z-ring structure at the future division site to regulate cell division in E.coli.The overexpression of FtsZ blocked the normal cell cycle and led to cell filamentation.