  The relativistic corrections to the static potential, i.e. the O(1/m)
correction, the O(1/m^2) spin-dependent and momentum-dependent corrections are
investigated in SU(3) lattice gauge theory. These corrections are relevant
ingredients of an effective field theory for heavy quarkonium called potential
nonrelativistic QCD. Utilizing the multilevel algorithm for the field strength
correlator on the quark-antiquark source, these corrections are determined at
the distances ranged from 0.25 to 1.2 fm. A reasonable scaling behavior and
long-range nonperturbative contributions are observed.
