The invention discloses an aqueous hyperbranched polymer emulsifier, and applications thereof in preparing water-borne epoxy resin emulsion. The aqueous hyperbranched polymer emulsifier is represented by formula (I). The aqueous hyperbranched polymer emulsifier is capable of dispersing oil soluble epoxy resin in water, and possesses high functionality degree (including hydrophilic groups, riveting groups, and compatibility group), and limited influence on viscosity is caused. The aqueous hyperbranched polymer emulsifier can be used for dispersing oil soluble epoxy resin in water so as to prepare a stable water-borne epoxy resin emulsion; the stable water-borne epoxy resin emulsion can be uniformly mixed with a waterborne curing agent, and an obtained mixture is subjected to solidification so as to obtain a high-performance solidification membrane to be used in the paint industry. The obtained high-performance solidification membrane can be directly taken as a varnish, or can be used for recombination with other substances so as to obtain a paint which is used for protecting base materials from corrosion in long term.