The invention provides a design method for a dual-power high-voltage reversing valve of an electro-hydraulic control valve set of a deep sea Christmas tree. The specific design method comprises the following four steps: determining a design scheme according to an actual use environment, checking and calculating a geometrical dimension, checking and calculating valve body operation force, and re-checking. The design method provided by the invention is reasonable, is high in calculating efficiency and precision, and a design value is more close to an actual use value, so that the reliability of the design work for the dual-power high-voltage reversing valve of the electro-hydraulic control valve set of the deep sea underwater Christmas tree is effectively improved, and therefore, the design method is beneficial for improving the stability and the reliability, in the actual use, of a valve body.