The induction heating process of slab steel had been discussed by finite element method. The results obtained were in good agreement to the measured value. In addition, the low-frequency induction heating process of slab steel was investigated and analyzed in detail according to the practice requirements of a steel mill. During the heating process of slab steel by low-frequency induction, the temperature increasing speed of surface is faster than that of center in initial time. With the increment of heating time, the temperature increasing speed of surface becomes lower because of the heat loss of boundary. A 90 percent of the slab steel temperature had risen from 1100°C to 1400°C with 110Hz and 6.2×106A/m2 after 30min, which could be satisfied with heating requirements.