The invention relates to a combined desulfuration dephosphorization method. The method comprises: firstly preparing an iron-based ionic liquid and a Fe-M based ionic liquid (M=Cu, Mn, Zn or Pd), then introducing a gas mixture of hydrogen sulfide and hydrogen phosphide into the iron-based ionic liquid for desulfuration, then introducing the gas mixture of hydrogen sulfide and hydrogen phosphide into the Fe-M based ionic liquid for dephosphorization, so as to realize combined removal of hydrogen sulfide and hydrogen phosphide in the system and obtain a purified gas, and regenerating the iron-based ionic liquid and the Fe-M based ionic liquid and realizing cycle use. The method is a green efficient technology for removing hydrogen sulfide and hydrogen phosphide, and is applicable to purify industrial raw gas, chemical industry production process gas, industry production tail gas and other systems containing hydrogen sulfide and hydrogen phosphide. The method also has the characteristics of relatively high removal efficiency, no secondary pollution, regenerable and recyclable removing agent, low cost and the like.