In the paper [Hong-Shi Zong, Wei-Min Sun, Phys. Lett. B 640 (2006) 196], the
authors claim that our proof of the inconsistency of the ladder approximation
to QCD [Phys. Lett. B 611 (2005) 129] was incorrect. However, their claim is
based on a derivation which contains a rough mathematical mistake, namely the
unjustified change of variables in the divergent (though regularized)
integrals. In this comment I will show this explicitly, so our conclusion that
the ladder approximation to QCD is inconsistent remains, of course, correct.Comment: 2 pages, no figure, no table