NOVELTY - Compound organic fertilizer preparation involves concentrating molasses fermented waste liquid, where the organic matter content is 40-75 %. The concentrated liquid is cooled, and then the concentrated liquid is divided into two parts, where the former part is used for alkaline hydrolysis, and latter part is used for acid hydrolysis. Alkaline hydrolysis is performed by taking former part of concentrated liquid. Alkaline hydrolysis liquid (10-35%) is added to the obtained material, and then stirred the obtained solution for 20-40 minutes to obtain demodulation base material.    USE - Method for preparing compound organic fertilizer used for Eucalyptus (claimed).    ADVANTAGE - The method enables to prepare compound organic fertilizer that has improved quality of Eucalyptus with disease resistance.    DETAILED DESCRIPTION - Compound organic fertilizer preparation involves concentrating molasses fermented waste liquid, where the organic matter content is 40-75 %. The concentrated liquid is cooled, and then the concentrated liquid is divided into two parts, where the former part is used for alkaline hydrolysis, and latter part is used for acid hydrolysis. Alkaline hydrolysis is performed by taking former part of concentrated liquid. Alkaline hydrolysis liquid (10-35%) is added to the obtained material, and then stirred the obtained solution for 20-40 minutes to obtain demodulation base material. Acid dehydration is performed by taking latter part of concentrated liquid. Acidic hydrolysis solution (10-35%) is added to the concentrated liquid, and then stirred the obtained mixture for 20-40 minutes to obtain demodulation acid material. Seasoning is added to the obtained demodulation acid material and demodulation base material, and then mixed uniformly to obtain acid-base neutralized liquid, where pH is 5-7. The obtained material is dried at 35-50 degrees C, where the water content is less than 10%. Sugar cane slag (15-30 pts.wt.), filter mud (50-70 pts.wt.) and dried acid-base neutralized liquid (10-30 pts.wt.) and base culture medium (2-5 pts.wt.) are mixed in a biological fermenting tank, and then fermented the mixed material in aerobic conditions for 10-15 days to obtain first-stage fermented fertilizer. The obtained first-stage fermented fertilizer, trace element (2-5 pts.wt.) and probiotics seed liquid (5-15 pts.wt.) are mixed, and then fermented the obtained mixture under aerobic conditions for 7-10 days. Calcium-magnesia phosphate fertilizer (10-15 %), potash fertilizer (10-15 %), humic acid (10-15 %) and bran fertilizer (10-15 %) are stirred uniformly to obtain active organic fertilizer, where the pH is adjusted by adding alkali agent or acid agent. The obtained material is dried at 40-60 degrees C to obtain organic compound fertilizer, where the water content is less than 10%.