The pearlite-to-austenite transformation during isothermal and uniform heating processes of classic bearing steels was studied using a dilatometer. The relationship between ferrite, cementite, and austenite during the transformation was investigated in detail. To explain the experimental phenomenon more theoretically, pearlite-to-austenite transformation was simulated using the DICTRA module of the Thermo-Calc software package based on a simplified model. Experimental results validated the pearlite-to-austenite transformation mechanism of low-alloy steel previously proposed. The transformation is controlled by Cr diffusion and C diffusion below and above the partition-to-no-partition temperature, respectively.