Cubic silicon carbide (3C-SiC) has superior mobility and thermal conduction than that of widely applied hexagonal 4H-SiC. Moreover, much lower concentration of interfacial traps between insulating oxide gate and 3C-SiC helps fabricate reliable and long-life devices like metal-oxide-semiconductor field effect transistors (MOSFETs). However, the growth of high quality and wafer-scale 3C-SiC crystals has remained a big challenge up to now despite of decades-long efforts by researchers because of its easy transformation into other polytypes during growth, limiting the development of 3C-SiC based devices. Herein, we report that 3C-SiC can be made thermodynamically favored from nucleation to growth on a 4H-SiC substrate by top-seeded solution growth technique (TSSG), beyond what’s expected by classic nucleation theory. This enables the steady growth of high-quality and large-size 3C-SiC crystals (2~4-inch in diameter and 4.0~10.0 mm in thickness) sustainable. The as-grown 3C-SiC crystals are free of other polytypes and have high crystalline quality. Our findings broaden the mechanism of hetero-seed crystal growth and provide a feasible route to mass production of 3C-SiC crystals, offering new opportunities to develop power electronic devices potentially with better performances than those based on 4H-SiC.