A scanning low-energy electron probe（SLEEP）is used to analyze the Work function distribution and variation of the surface.with a slow sweep circuit to simplify the measuring system.Impregnated dispenser cathodes（IDC）and oxide cathodes are investigated using the SLEEP.heir work function distribution apears to have evident differences at vari- ous states.The IDC has a more uniform work function distribution than an oxide cathode. The work function distribution of an activated cathode well corresponds to Gaussian distribu- tion.The phenomena of low energy electron reflection in single crystal silicon and tungsten are also observed by using this technique.The position of the conduction band edge with re- spect to Fermi level Ec and electron affinity of Si（100）are measured

the former being about 1.2eV and the latter about 3.6eV.