  The features of magnetic field in relativistic heavy-ion collisions are
systematically studied by using a modified magnetic field model in this paper.
The features of magnetic field distributions in the central point are studied
in the RHIC and LHC energy regions. We also predict the feature of magnetic
fields at LHC $\sqrt{s_{NN}}$= 900, 2760 and 7000 GeV based on the detailed
study at RHIC $\sqrt{s_{NN}}$ = 62.4, 130 and 200 GeV. The dependencies of the
features of magnetic fields on the collision energies, centralities and
collision time are systematically investigated, respectively.
