The present invention relates to a method of preparing a hyperbranched polyether ester. According to the present invention, a di-functionality haloalkane and a tri-functionality hydroxyl/carboxyl benzene are used as raw materials, and the hyperbranched polyether ester is synthetized in one pot with an A2+B3 polymerization method. The present invention is featured by easily obtained raw materials and simple steps, and the prepared hyperbranched polyether ester contains end groups with high reactive activity, so that various functional groups or polymer chains can be introduced into the hyperbranched polyether ester by a further condensation reaction, ring-opening reaction, etc., and thus a hyperbranched polymer with a diversity of properties and unique functions can be prepared.