The temperature distribution of SiC single crystal growth cavity in PVT method is an important factor affecting the crystal quality. The effects of insulation structure, crucible structure and coil position on the growth temperature field of 6-inch SiC crystal were investigated by numerical simulation. The temperature distribution suitable for high-quality 6-inch SiC crystal growth is optimized. The 6-inch SiC crystal without cracks is successfully obtained through this temperature field. Also, the quality of the SiC wafer was characterized by high resolution X-ray diffraction, Raman spectroscopy and defect detection system. The results show that the crystal is single 4H-SiC, the micropipe density is less than 1 cm-2, the resistivity range is 0.02-0.022 Ω?cm, and the full width at half maximum of X-ray rocking curve is 21.6″.