The invention discloses a ferric oxide pigment paste and a preparation method of the ferric oxide pigment paste. A surface modifier having the structure as shown in the general formula (I) is used tomodify the surface of a ferric oxide pigment, the ferric oxide pigment is grafted on the surface of the pigment through a covalent bond, the interspace diffuse resistance among pigment particles is improved, so that the stability is improved, the fineness is reduced, and the tinting strength is improved; a polyurethane dispersant having the structure as shown in the general formula (II) is introduced and is compounded with other dispersants, so that the stability and the tinting strength are obviously improved, the polyurethane dispersant having the structure as shown in the general formula (II) comprises a plurality of anchoring fixation groups, the anchoring fixation effect on the surface of the pigment is good, and the anchoring fixation groups are favorable for the dispersion and the stability of the pigment particles in the paste; and therefore, the paste has the advantages of high storage stability, small fineness and high tinting strength.