The invention relates to a preparation method of 3, 4 '-
diaminodiphenyl ether (3, 4'-ODA). A first aspect of the present application relates to a method for preparing 3-amino-4 '-nitrodiphenyl
ether, comprising: (1) synthesizing 3-amino-4'-nitrodiphenyl
ether from p-
nitrochlorobenzene, m-aminophenol in a first
solvent in the presence of a condensing agent wherein the first
solvent is selected from sulfones, sulfoxides, amides, phosphamides, and step (1) is carried out under reduced pressure, and step (2) is carried out under reduced pressure; and removing the generated water during the proceeding of the step (1). The invention relates to a method for preparing 3, 4 '-ODA in the second aspect, and the method comprises the steps of (a) preparing 3-amino-4'-nitrodiphenyl
ether through the method in the first aspect, and (b) reducing the 3-amino-4 '-nitrodiphenyl ether obtained in the step (a) in the presence of a
reducing agent to obtain the 3, 4'-ODA. The invention further relates to the 3, 4 '-ODA obtained through the method in the second aspect.