The products of hot continuous roll casting, which has the feature of being a short process, have some quality defects. A new concept that a compound magnetic field is applied to the roll casting zone so as to force it to nucleate, restrain crystal growth and obtain a fine equiaxed grain structure because of the action of electromagnetic Lorentz force has been put forward in this paper. Not only have the design model of the electromagnetic field (EMF) and the technological realization of electromagnetic roll casting (EMRC) been discussed based on experiments and research of laboratory and industrial trials, but the matching and coupling relationship between the electromagnetic parameters and technical parameters of roll casting on the basis of the structure and performance of materials have been investigated.