The invention discloses a repair method of arsenic-polluted soil. The repair method comprises the following steps: 1) activation: an activating agent is added in the arsenic-polluted soil, and is uniformly stirred for reaction; 2) oxidation: manganese dioxide is added in the arsenic-polluted soil activated in the step 1), and is uniformly stirred for oxidation; 3) stabilization: a stabilizing agent is added in the arsenic-polluted soil oxidized in the step 2), and is uniformly stirred for standing; and 4) acid and alkali adjustment: plant ash is added in the arsenic-polluted soil stabilized in the step 3), is uniformly stirred, and is naturally cultivated; and meanwhile, the water content of the soil is adjusted. The repair method combines a leaching technology with a stabilizing technology, and is simple in operation, wide in raw material source and excellent in stabilizing effect.