This invention relates to a method for preparing self-emulsifying waterborne epoxy curing agent emulsion, which is composed of: primary amine 7-20 wt.%, epoxy resin 12-27 wt.%, epoxy-terminated polyether 3-8 wt.%, epoxy active diluter 10-30 wt.%, and deionized water 35-60 wt.%. The method comprises: adding primary amine into a reactor, slowly dropping a mixture of epoxy resin and epoxy-terminated polyether, reacting at a certain temperature, slowly dropping monofunctional epoxy active diluter, reacting, adding water, and emulsifying to obtain white waterborne epoxy curing agent emulsion. The method has such advantages as simple process, low reaction temperature (below 100 deg.C), high safety and low energy consumption. The obtained waterborne epoxy curing agent emulsion has such advantages as low VOC content, high stability, high water resistance, high compatibility with epoxy resin, high impact resistance, good luster, high toughness and high adhesiveness, and can be used in paint, adhesive and polymer concrete.