  We study Witten's proposal that a domain wall exists in M-theory fivebrane
version of QCD (MQCD) and that it can be represented as a supersymmetric
three-cycle in G_2 holonomy manifold. It is shown that equations defining the
U(1) invariant domain wall for SU(2) group can be reduced to the Monge-Ampere
equation. A proof of an algebraic formula of Kaplunovsky, Sonnenschein and
Yankielowicz is presented. The formal solution of equations for domain wall is
constructed.
