A process for using solid alkali and agent-alkali to deeply desulfurizing the liquefied petroleum gas and light hydrocarbon features that the raw material to be treated passes sequentially through liquid alkali (or solid alkali) washing tank (or tower), liquid-liquid countercurrent extracting tower, and settling separation tank to separate out the refined product and extracting liquid. The agent-alkali liquid also passes through oxidizing regeneration tower and back extracting tower for cyclic use.