  Starting from the Kubo formula and the the QCD low energy theorem, we study
the the bulk viscosity of hot dense quark matter in the PNJL model from the
equation of state . We show that the bulk viscosity has a sharp peak near the
chiral phase transition, and the ratio of bulk viscosity over entropy rises
dramatically in the vicinity of the phase transition. These results agrees with
that from lattice and other model calculations. In addition, we show that the
increase of chemical potential raises the bulk viscosity.
