The growth behavior of carbon nanotubes (CNTs) grown on electron bombarded catalyst layer has been investigated in this paper. A hot cathodic electron beam facility was employed to electron bombarding of catalyst layer before stage of CNTs growth. The growth of carbon nanotubes was performed on the Fe catalyst layer with sio2 substrate in an environment of different mixed gases (H2, NH3 and C2H2) by Thermal Chemical Vapor Deposition (TCVD) system. The pretreated substrates were probed by Atomic Force Microscopy (AFM) and CNTs grown was confirmed by Raman spectroscopy. Moreover, all samples were analyzed by Scanning Electron Microscopy (SEM) before and after growth of CNTs. SEM analyzes clarified that the catalyst grains has been smaller under effect of electron beam bombardment.