  The spin Hall effect in two dimensional hole systems is studied by using the
four-terminal Landauer-B\"{u}ttiker formula with the help of Green functions.
The spin Hall effect exists even when there are {\em not} any correlations
between the spin-up and -down heavy holes (light holes) and when the
$\Gamma$-point degeneracy of the heavy hole and light hole bands is lifted by
the confinement or recovered by the strain. When only a heavy hole charge
current without any spin polarization is injected through one lead, under right
choice of lead voltages, one can get a pure heavy (light) hole spin current,
combined with a possible impure light (heavy) hole spin current from another
two leads. The spin Hall coefficients of both heavy and light holes depend on
the Fermi energy, devise size and the disorder strength. It is also shown that
the spin Hall effect of two dimensional hole systems is much more robust than
that of electron systems with the Rashba spin-orbit coupling and the spin Hall
coefficients do not decrease with the system size but tend to some nonzero
values when the disorder strength is smaller than some critical value.
