  The improved quark mass density-dependent (IQMDD) model, which has been
successfully used to describe the properties of both infinite nuclear matter
and finite nuclei, is applied to investigate the properties of quark
deconfinement phase transition. By using the finite-temperature quantum field
theory, we calculate the finite temperature effective potential and extend the
IQMDD model to finite temperature and finite nuclear matter density. The
critical temperature and the critical density of nuclear matter are given and
the QCD phase diagram is addressed. It is shown that this model can not only
describe the saturation properties of nuclear matter, but also explain the
quark deconfinement phase transition successfully.
