The invention discloses a magnetizing inrush current combined blocking method based on waveform symmetry. The magnetizing inrush current combined blocking method comprises the following steps of: S01, differential current calculation; S02, waveform asymmetry judgment of differential current at current sampling moment; S03, waveform asymmetry judgment within a cycle time; S04, combined blocking logic, including adopting combined logical blocking differential protection according to the waveform asymmetry situations of differential currents of the A phase, B phase and C phase obtained in the step 03; the magnetizing inrush current combined blocking method is provided starting from technical defects existing in the current methods, comprehensively considering various forms of the magnetizing inrush current waveforms and influence of the magnetizing inrush current on identification of a short trouble, and combining with innate phase angle conversion characteristic of a power transformer; the method can effectively distinguish the magnetizing inrush current and fault current, thus being beneficial to improving reliability and rapidity of differential protection of the transformer.