The invention discloses a finite element and finite different coupling method for fast calculating rolled piece section temperature. The method includes the steps of firstly, mapping finite element grids before rolling of each gate with finite difference grids before rolling, and transmitting finite different grid node temperature before rolling to the finite element grids before rolling according to position relations; secondly, transmitting finite element node temperature before rolling to finite element nodes after rolling, and adding rolling temperature rise; thirdly, performing finite difference grid division on rolled pieces according to the finite element grid data of the rolled piece after the rolling of each gate, and judging in-surface, out-surface and boundary point positions; fourthly, mapping the finite element grid node temperature to finite difference nodes according to position relations; fifthly, using finite difference grids to perform gap temperature calculating after rolling. By the method, the instant temperature fields at optional moment during rolling of the rolled pieces with various sections can be calculated fast, calculation speed is increased greatly, manual intervention is not needed, and high automation level is achieved.