The invention provides an ex-situ chemical restoration system of polluted soil. The system is sequentially provided with a pretreatment device, a storage bin, a primary reactor, a secondary reactor and a maintenance device, a first conveying device used for conveying is arranged between the pretreatment device and the material inlet of the storage bin, a second conveying device used for conveying is arranged between the material outlet of the storage bin and the material inlet of the primary reactor, the material outlet of the primary reactor corresponds to the material inlet of the secondary reactor, and a third conveying device used for conveying is arranged between the material outlet of the secondary reactor and the maintenance device. The invention provides an ex-situ chemical restoration method of polluted soil. The ex-situ chemical restoration system of polluted soil allows a liquid or solid reagent to be quantitatively added, can continuously automatically run or intermediately run, can control the reaction time to guarantee the ex-situ chemical restoration effect of the polluted soil, realizes uniform mixing and stirring, is simple to operate, and can be widely applied to the ex-situ chemical restoration of the polluted soil.