Some phys-metallurgical problems related to direct spheroidization of carbide in the process of fine-rolling were analyzed and investigated in this paper in accordance with the author's viewpoint that the morphology of carbide phase in product of eutectoid reaction might be affected by grain size of austenite mother-phase in steels. It is concluded that when a hypoeutectoid steel with super-cooled mono-phase austenite microstructure is fine-rolled at the temperature bellow the equilibrium point of Ae1 in Fe-C diagram, the austenite grains would be refined due to previous' over-precipitation' of ferrite along grain boundaries and deformation bands. At the same time, the eutectoid reaction of intra-grains instead of that along the boundary is induced with the inerease of the rolling rate. While the as-rolled steel stays briefly at the rolling temperature, carbide in the steel may be better spheroidized.