The temperature uniformity and heating efficiency in a high-temperature epitaxial growth system were investigated by modeling and simulating. The finite element method (FEM) was used to calculate the distribution of magnetic field and temperature field in the reactor of growth system. The simulation results showed that due to the skin effect and heat conduction in the conventional susceptor, the temperature distribution of the wafer on the susceptor is not uniform. However, the temperature uniformity of the wafer can be greatly improved by adding an air gap below the wafer. The existence of air gap effectively reduced the temperature on the center of the wafer, and the effect of its radius on temperature uniformity was studied. By calculating different frequencies and coil currents, the temperature and heating rate in the reactor with modified susceptor were investigated. The results indicated that higher temperature and faster heating rate can be obtained by increasing heating frequency and coil current. However, both lower and higher frequency will bring worse temperature uniformity.