The invention relates to a method for removing water in an acrylic acid aqueous solution, which comprises the following steps of: mixing a monomer or composite azeotropic agent with an acrylic acid aqueous solution, so a lowest azeotrope is formed by the azeotropic agent and the water in the acrylic acid aqueous solution; heating and evaporating a mixing solution of the azeotrope and the acrylic acid aqueous solution under a vacuum condition, wherein the tower top temperature is azeotropic temperature of the azeotropic agent and the water under the pressure; gasifying the lowest azeotrope which is formed by the azeotropic agent and the water in the acrylic acid aqueous solution, and separating the gasified lowest azeotrope from the solution; and condensing the lowest azeotrope into a liquid phase by a condensing cooler, wherein the condensed liquid phase includes an azeotrope layer and a water layer, collecting the water layer, and returning the azeotrope layer to mix with the acrylic acid aqueous solution for recycle. The method disclosed by the invention can effectively remove the water; the content of water in the acrylic acid aqueous solution is reduced to be lower than 0.1% (wt); and the azeotropic agent is recovered by a recovery rate of 90% with low energy consumption.