To address the issues of low measurement accuracy and insufficient stability in traditional calibration methods for Shack-Hartmann wavefront sensors (SHWFS), we propose a high-precision absolute calibration method using spherical waves generated by sensor. A high-precision calibration method for spherical waves was obtained through theoretical derivation. Combined with the constructed spherical wave calibration experimental device, high-precision calibration was performed on the SHWFS with sub apertures of 128×128. The structural parameters of the SHWFS (f, w, and L₀) are calculated precisely. The measurement accuracy of the SHWFS is verified after calibration. The experimental results demonstrate that by using this method to calibrate the SHWFS, its wavefront recovery accuracy reaches a PV of 1.376×10^-2λ and an RMS of 4×10^-3λ (where λ=625 nm), respectively. Additionally, its repeatability accuracy reaches a PV of 3.2×10^-3λ and an RMS of 9.76×10-4λ (where λ=625 nm), respectively. These findings suggest that this method is suitable for enhancing the measurement accuracy of high-precision calibration of SHWFS with large aperture.