The classic preparation process of azithromycin can be divided into 4 sections, which are oximation, Beckmann rearrangement, reduction and methylation. Erythromycin 6,9-imino ether as one of the important intermediates in the preparation process of azithromycin, differences in their preparation and crystallization conditions directly affect the quality and yield, also cause a certain degree of influence on the environment at the same time. From the aspects of environmental protection, the feasibilities in preparation and crystallization process of erythromycin imino ether, the COD in wastewater can be reduced, by adopting aromatic hydrocarbons instead of water soluble solvent in crystallization proess the energy waste in the solvent recovery process can be reduced, and energy consumption can be reduced at the same time.