NOVELTY - Stratification of ortho-phenylenediamine post-reduction material, comprises mixing ortho-chlorobenzene with aqueous ammonia, carrying out ammoniation reaction, taking into a reduction pot, adding sodium sulfide, reducing, reducing temperature, analyzing in a stratified tank under nitrogen environment, allowing to stand, heating with hot water, taking o-phenylenediamine and salt hydrate into a stratified tank two graded layer, evaporating water, heating, connecting, carrying out stratification and cleaning inside of the pipeline.    USE - The method is useful for stratification of ortho-phenylenediamine post-reduction material.    ADVANTAGE - The method: saves energy; shortens working time; reduces distillation residue; provides necessary conditions for rectification; produces high quality o-phenylenediamine; increases carbendazim productivity; improves recovery process of o-phenylenediamine; is economical; improves operating environment; and reduces labor intensity.    DETAILED DESCRIPTION - Stratification of ortho-phenylenediamine post-reduction material, comprises (i) mixing ortho-chlorobenzene with aqueous ammonia and carrying out ammoniation reaction to obtain ortho-nitroaniline, (ii) taking into a reduction pot, adding sodium sulfide and reducing, (iii) reducing temperature to 85-90 degrees C, analyzing in a stratified tank under nitrogen environment at 0.1-0.3 MPa to obtain a first graded dividing layer groove, allowing to stand, heating with hot water at 80-85 degrees C through stratified tank discharge pipe, removing ortho-phenylenediamine and salt hydrate, removing first grade dividing groove lower part layer through U-shaped tube and separating liquor and material, (iv) taking o-phenylenediamine and salt hydrate into a stratified tank two graded layer, maintaining temperature at above 120 degrees C, evaporating water, maintaining stratified tank lower part temperature at 100-120 degrees C, heating stratified tank lower part with steam and connecting top part of the stratified tank with recovery tank, (v) reducing stratified tank middle part material salinity to 45-55%, connecting second grade dividing groove layer into first grade dividing groove lower part layer through pump, carrying out stratification, reducing salinity of the lower part material, stopping, cleaning inside of the pipeline through steam and ensuring pipeline outlet in the upper part of the liquid material.