Rare earth saponifying method of acidic phosphinic extractant

The invention discloses a rare earth saponifying method of an acidic phosphinic extractant. The method is characterized in that hydroxide strongly basic styrene type anion exchange resin is used as a promoter to realize the rare earth saponifying of an acidic phosphinic extractant P507, P229 or C272. The method comprises the following steps: sequentially adding a kerosene or sulfonated kerosene solution of the acidic phosphinic extractant, a rare earth chloride aqueous solution and the hydroxide strongly basic styrene type anion exchange resin to a saponifying reactor; fully stirring to react under the room temperature; then standing after reaction to layer, wherein the upper layer is a rare earth saponifying organic phase of the acidic phosphinic extractant, the middle layer is an aqueous phase, and the lower layer is a solid strongly basic styrene type anion exchange resin phase; removing the water phase and the strongly basic styrene type anion exchange resin phase to obtain the rare earth saponified acidic phosphinic extractant organic phase at the saponifying rate of 30 to 45%. The method has the advantages of improving the product purity, decreasing the production cost, and saving the energy.