In recent years, in order to meet the development needs of a new generation of infrared focal plane detectors with megapixels, high integration and high performance, the demand for InSb wafers with high lattice quality and high surface state is increasing. In order to improve performance of the InSb wafers processed with as-grown crystal, the high temperature heat treatment of the wafer is studied. The inherent defects of crystal growth and the process defects introduced by wafer processing are optimized through using a specially designed wafer loading device combined with the corresponding heat treatment method. The stoichiometric ratio of the InSb wafer is improved, and the residual stress inside the wafer is released. The quality of the crystal lattice is improved, the flatness of the whole wafer is optimized, and the overall quality of the InSb wafer is finally improved, which laid a material foundation for the production of high performance and large size infrared focal plane detectors.