The invention belongs to the related technical field of mechanical structure dynamics vibration calculation and analysis, and discloses a high-precision transfer function sampling method. The transfer function sampling method comprises the following steps of (1) constructing a dynamic equation of a mechanical system; (2) obtaining a system vibration frequency by a system vibration mode calculation method; (3) setting a sampling mode, a sampling bandwidth, and a sampling number to generate a basic transfer function sampling frequency point sequence; (4) extracting a mode frequency in the transfer function analysis bandwidth and setting the total number of corresponding refined sampling point to form a corresponding refined sampling point sequence of the mode frequency in the transfer function analysis band width; (5) combining the basic transfer function sampling frequency point sequence with the refined sampling point sequence to generate a final transfer function sampling frequency point sequence; (6) conducting a transfer function numerical calculation to the final transfer function sampling frequency point sequence to obtain a transfer function graph of final discrete data.