Abstract: Taking benzophenone hydrazone（BPH ）as an example ，explores the method of purifying BPH waste residue to BPH complying with industrial standard. With the decoloring and edulcorating feature of active carbon，chooses the amount of solvent ，the amount of active carbon，the reflux time ，obtains the white highly purified product from yellow waste residue and the suitable technological conditions ：solvent cyclohexane 13∶1（mass ratio with waste residue），active carbon 5 %（mass fraction of waste residue），reflux time 2 hours.

Key words: Industrial residue , benzophenone hydrazone , technology