The invention provides an elevation correction method for critical coronal voltage of hardware fittings of high-elevation transmission lines. The elevation correction method is based on data of corona discharge characteristic of hardware fittings at simulated elevation in tests carried out in an ultra-high-voltage alternating-current test base environment and climate laboratory, and the correction method realizes exponential-form fitting, and can be applied to elevation correction calculation for design and optimal research for the high-elevation 330-kV alternating-current transmission lines. The elevation correction method has the advantages that calculation for elevation correction factors for the hardware fittings of the 330-kV alternating-current transmission lines in high-elevation areas is provided, equipment size and design basis meeting actual running requirements are provided, and simultaneously, fundamental data and reference for optimization and improvement operation of the hardware fittings are provided.