The silicate-based molten slag plays a crucial rule in the prosses of continuous casting as functional materials. In the present study, the influences of magnetic field intensity and frequency on melting temperature of mould flux are revealed by an experimental method. To achieve this, a conductivity electrode and a measurement device are implemented to measure the melting temperatures under various magnetic field intensities and frequencies. The tested results show that with the increasing of magnetic field intensity (0~30mT), the melting temperature of mould flux increases by 11~12K. When the magnetic field intensity is 20mT, the frequency increases 6Hz, the melting temperature of the slag is increased by 0.4~1.6K. Additionally, it is found that, according to the melt solidification theory, the potential barrier requires to be overcome when the flux melts from liquid phase to solid phase, and the barrier can be weakened when electromagnetic force is applied.