  We study the pion-nucleon sigma term in vacuum and in nuclear matter in the
framework of global color model of QCD. With the effective gluon propagator
being taken as the $\delta$-function in momentum space of Munczek-Nomirovsky
model, we estimate that the sigma term at chiral limit in the vacuum is 9/2
times the current quark mass and it decreases with the nuclear matter density.
With the presently obtained in-medium pion-nucleon sigma term, we study the
in-medium chiral quark condensate and obtain a reasonable variation behavior
against the nuclear matter density.
