The invention relates to a detection method and system of high-voltage DC converter commutation parameters. The method comprises the following steps: converting a, b and c three-phase voltages at a converter transformer network side, obtained by a converter station through measurement to obtain AC voltage fundamental wave positive-sequence component phases of the converter transformer network side; according to the voltage fundamental wave positive-sequence component phases of the converter transformer network side, calculating fundamental wave positive-sequence components and fundamental wave negative-sequence components of the converter transformer network side; according to the voltage fundamental wave positive-sequence component phases of the converter transformer network side, the fundamental wave positive-sequence components and the fundamental wave negative-sequence components, calculating tertiary positive-sequence components and tertiary negative-sequence components of AC voltages; and according to the voltage fundamental wave positive-sequence component phases of the converter transformer network side, the fundamental wave positive-sequence components, the fundamental wave negative-sequence components, the tertiary positive-sequence components and the tertiary negative-sequence components, determining an actual commutation voltage zero-crossing point, a commutation angle and an effective trigger angle of a converter. By use of the method and system, the converter commutation parameters can be accurately measured, and the performance of a high-voltage DC power transmission system can be improved.