Calmodulin is currently regarded as a central component in a complex regulatory system in the eukaryotic cell and imposes control upon many of the essential metabolic and physiological functions of the cells.But the attempts to find such calmodulin-like-protein in prokaryotes always gave controversial condusion before. Since the first calmodulin-like-protein was found in E. coli in the early 1980s,the protein factors have been detected in many kinds of prokaryotes,and their regulatory functions have been found in sporulation, cell fission of bacteria, heterocyst cyto-differentiation, N₂ fixation and photosynthesis in cyanobacteria etc. The recent research progress in the field was reviewed.