Aiming at the difficulty of non-contact measurement of the casting and forging′ s internal temperature field under high temperatures and severe conditions, a reconstruction method for the temperature field of high-temperature castings and forgings with noncontact oblique incident shear wave ( S-wave) electromagnetic acoustic transducer ( EMAT) based on the bending effect and the triangular forward expansion method is proposed. Combining the numerical simulations and EMAT testing experiments at 730℃ , the triangle tracking mathematical model of direct incident S-waves is evaluated. The effects of sound beam incident angle and temperature gradient on the propagation path and flight time of oblique incident S-wave are studied, and the temperature sensitivity coefficients of oblique incident S-wave with different incident angles are compared. Results show that the reconstruction error of direct incident S-waves in the temperature field of the high-temperature forging based on the triangular forward expansion method is within 3% . When the oblique incident S-wave is used, the propagation path of sound ray is greatly affected by the temperature gradient and the incidence angle, and it is more sensitive to the change of temperature gradient. The internal temperature field of high-temperature casting can be reconstructed by the flight time of the S-wave and the offset of the exit point of the S-wave.