The invention discloses a high hydrophilic polyamidoimide, the preparation method thereof and the application thereof in porous membranes, belonging to the technical field of polymer materials. The preparation method comprises the following steps: citrate and aliphatic diamine are mixed evenly by the mol ratio of 1:0.1 to 1:10, catalyst with the ratio being 0.1-10 wt percent of the gross weight of the citrate is added in the reactants and is mixed evenly with the reactants to have condensation polymerization to form a midbody after being heated and depressurized in vacuum, and the high hydrophilic polyamidoimide is obtained after the midbody is gradually heated in a temperature range of 50-250 DEG C for continuous reaction. When the invention is applied to a microporous film, the reactionmass is paved on the surface of glass or metal, a liquid membrane with a certain thickness is cast, and the liquid membrane is gradually heated in a temperature range of 50-250 DEG C by stages in vacuum for 2-24 hours so that the porous membrane with the aperture of 0.1-2.0 micron is formed. The hydrophilicity of the high hydrophilic polyamidoimide prepared by the invention is 3-15 times higher than that of regular aromatic polyamide imide.