The invention discloses a self-restoring three-mode redundancy structure for defending single-particle soft error accumulation. A single-particle soft error detection circuit and a data selection circuit are added to perform optimized design on a circuit, the design based on the structure can automatically restore after single-path signal overturning in the three-mode redundancy structure, and theproblem that the three-mode redundancy structure may cause single-particle reinforcement failure due to error accumulation is effectively solved.