The invention provides a homogeneous phase anion exchange membrane and a preparation method thereof, which relate to an anion exchange membrane and a preparation method thereof. The invention solves the problems that the prior process for preparing a heterogeneous anion exchange membrane causes serious pollution to the environment, and the product has poor ion selective permeability, poor electrochemical properties and poor anti-pollution capability. The homogeneous phase anion exchange membrane is prepared from polysulfone, polytetrafluoroethylene, epoxy chloropropane, ethyl vinyl alcohol, acatalyst and an organic solvent. The method comprises the following steps: firstly, weighing raw materials; secondly, adding the polysulfone and the polytetrafluoroethylene into the organic solvent, and mixing the materials to obtain slurry solution; thirdly, adding the epoxy chloropropane, the ethyl vinyl alcohol and the catalyst to the slurry solution, and mixing and defoaming the mixture to obtain casting membrane solution; fourthly, preparing a membrane, and drying the membrane after stripping; and fifthly, impregnating the membrane in trimethylamine solution, cleaning the membrane, impregnating the membrane in HCl solution, and cleaning the membrane to obtain the homogeneous phase anion exchange membrane. The homogeneous phase anion exchange membrane and the method are free from causing environmental pollution, the anti-pollution capability of the membrane is improved, the ion-selective transmission coefficient is up to between 0.94 and 0.96, and the conductivity of the membrane is increased by 10 percent compared with that of a heterogeneous membrane.