The geometry, electronic structure and electronic transmission of Au electrode-compressed C-20 fullerene-Au electrode systems are investigated systemically, and some interesting results are obtained by use of molecular dynamics, Extend Huckel method of the first principle, and Green's function based method. The analytical results show that, due to intervention of Au electrodes, the electronic structure of compressed C-20 fullerene is changed significantly, the coalescent between C-20 fullerene and Au electrodes is intervenient of covalent bond and electrovalent bond, and the compressed C-20 fullerenes are better conductors of electricity than those uncompressed or slightly compressed ones. The methods and the relative conclusions are beneficial to go further deep into electronic transmission of carbon fullerenes.