  The Skyrme energy-density functional approach has been extended to study the
massive heavy-ion fusion reactions. Based on the potential barrier obtained and
the parameterized barrier distribution the fusion (capture) excitation
functions of a lot of heavy-ion fusion reactions are studied systematically.
The average deviations of fusion cross sections at energies near and above the
barriers from experimental data are less than 0.05 for 92% of 76 fusion
reactions with $Z_1Z_2<1200$. For the massive fusion reactions, for example,
the $^{238}$U-induced reactions and $^{48}$Ca+$^{208}$Pb the capture excitation
functions have been reproduced remarkable well. The influence of structure
effects in the reaction partners on the capture cross sections are studied with
our parameterized barrier distribution. Through comparing the reactions induced
by double-magic nucleus $^{48}$Ca and by $^{32}$S and $^{35}$Cl, the
'threshold-like' behavior in the capture excitation function for $^{48}$Ca
induced reactions is explored and an optimal balance between the capture cross
section and the excitation energy of the compound nucleus is studied. Finally,
the fusion reactions with $^{36}$S, $^{37}$Cl, $^{48}$Ca and $^{50}$Ti
bombarding on $^{248}$Cm, $^{247,249}$Bk, $^{250,252,254}$Cf and
$^{252,254}$Es, and as well as the reactions lead to the same compound nucleus
with Z=120 and N=182 are studied further. The calculation results for these
reactions are useful for searching for the optimal fusion configuration and
suitable incident energy in the synthesis of superheavy nuclei.
