The hot-rolled GCr15 bearing steels were obtained by different cooling rates before pearlite transformation temperature through dynamic thermal simulation test, and followed by some spheroidizing annealing and quenching-tempering treatment. The relationship between the condition of proeutectoid carbide precipitation, microstructure-mechanical properties of hot-rolled bearing steel, heredity in microstructure-mechanical properties and fatigue life after heat treatment was investigated comprehensively. Results showed that as the cooling rate decreased from 100 °C/s to 0.5 °C/s, the proeutectoid carbide thickness and continuity both linearly increased from 0.04 µ m and 0.05 to 0.72 µ m and 0.93. The morphology of proeutectoid carbide changed from the small and dispersed strips to the thick and big networks. The tensile strength and percentage of area reduction of hot-rolled bearing steel both decreased. During heat treatment, the thick and big carbide networks could not be eliminated. The carbide precipitations by spontaneous nucleation in spherical form and non-spontaneous nucleation with the undissolved carbide strips as cores during spheroidizing annealing process were observed by high-temperature confocal laser scanning microscopy. The thickness and inhomogeneity of carbide in annealed and tempered microstructures both increased gradually. Finally, the strength and plasticity of heat-treated bearing steel still decreased, the fatigue life decreased by 91%. The tensile fracture changed from the quasi-cleavage fracture to the intergranular and quasi-cleavage fracture.