Abstract: The conventional heat treatment process for GCr15 bearing steel often struggles to simultaneously achieve sufficient dissolution of carbides and refinement of the pearlite structure, which limits the improvement of its comprehensive mechanical properties. In order to realize both sufficient carbide dissolution and pearlite refinement, the cyclic heat treatment process is applied to GCr15 bearing steel. This work aims to provide a theoretical basis and experimental reference for the development of new heat treatment processes for high-performance bearing steels. This paper mainly explored a new type of austenitization process, which not only enabled the full dissolution of carbides, but also refined the pearlite structure, achieving uniform distribution of fine carbides and improving the comprehensive performance of GCr15 bearing steel. This study applied a cyclic austenitizing process to GCr15 bearing steel. The evolution of pearlite and carbides and their effect on mechanical properties were investigated based on the phase transformation characteristics and microstructure evolution of undercooled austenite under different cycle numbers. The results show that with increasing cycle numbers, the pearlite interlayer spacing decreases from （320±17） nm in the one-cycle （C-1） sample to （268±22） nm in the two-cycle （C-2） sample and to （226±14） nm in the four-cycle （C-4） sample. The pearlite colony size also gradually reduces from 7.22 μm （C-1） to 6.02 μm （C-2） and then to 5.38 μm （C-4）. Meanwhile, the average size of carbides decreases from 0.48 μm （C-1） to 0.36 μm （C-2） and then to 0.25 μm （C-4）, and the Cr mass fraction in carbides increases gradually from 5.33% to 7.06% and then to 9.43%. Mechanical property results indicate that the strength and elongation of the C-2 sample are better than those of the C-1 and C-4 samples. Although the C-4 sample exhibits the finest pearlite interlayer spacing, colony size, and carbides, partial lamellar melting leads to microstructural heterogeneity. During tensile testing, this heterogeneity causes uneven strain distribution, promoting early crack initiation and thus reducing mechanical properties. Therefore, the C-2 sample has a more uniform microstructure and smoother work hardening rate dσ/dε curve, resulting in better combination of strength and toughness.