  Searching of the critical endpoint of the phase transition of Quantum
Chromodynamics~(QCD) matter in experiments is of great interest. The
temperature in the fireball of a collider is location dependent, however, most
theoretical studies address the scenario of uniform temperature. In this work,
the effect of temperature gradients is investigated using lattice QCD approach.
We find that the temperature gradient catalyzes chiral symmetry breaking,
meanwhile the temperature gradient increases the Polyakov loop in the confined
phase but suppresses the Polyakov loop in the deconfined phase. Furthermore,
the temperature gradient decreases the pseudo-critical temperature of chiral
transition but increases the pseudo-critical temperature of the
confine/deconfine transition.
