Abstract: Carbon nanotubes and nanofibers（CNTs-CNFs） composite films synthesized using different catalysts（Fe and Ni） on the graphite by low pressure and low temperature thermal chemical vapor deposition were used as electrodes for capacitive deionization.Several experiments were conducted to investigate the electrosorption performance of CNTs-CNFs composite film electrodes synthesized using different catalysts.The results showed that the electrosorption capacity of the CNTs-CNFs grown on Ni-sputtered graphite was larger than the one of the CNTs-CNFs grown on Fe-sputtered graphite,which means that the CNTs-CNFs grown on Ni-coated graphite was more suitable for electrosorption.Furthermore,the electrosorption of CNTs-CNFs follows Langmuir isotherm,indicating monolayer adsorption.