The invention discloses a composite microbial 
fertilizer and a preparation method thereof. The composite microbial 
fertilizer is composed of organic matters, 
nitrogen, 
phosphorus, 
potassium, functional microbes, rooting and 
seedling strengthening agent, polypeptide amino acids, secondary and minor elements, newly planted 
eucalyptus soil activating 
enzyme and a water-retaining and drought-resisting agent. The composite microbial 
fertilizer contains more than 40% of organic matters, 10% of 
humic acid, 3% of amino acids, 20% of 
nitrogen+
phosphorus+
potassium elements, more than 10% of secondary elements (
calcium, 
magnesium and 
sulfur), 2% of minor elements (
silicon, 
boron, 
zinc, 
manganese, 
copper, iron and 
molybdenum), and more than 20 million / g of complex functional bacterium and multiple enzymes. The preparation method comprises the following steps: fermenting before production, performing by complexing, rotting the organic matters, carrying out innocent treatment, weighing according to the optimal parts by weight, mixing and bagging. The composite microbial fertilizer improves the 
soil properties, increases the 
sugar degree by 2-3 degrees, is ecological and environment-friendly, and is capable of enhancing the soil productivity, increasing the 
soil nutrients and enhancing the bioactivity of the soil; and the 
disease prevention ratio is up to 70%, and the absorption and utilization ratio is up to 80%.