NOVELTY - Preparing composite soil using kitchen waste, sludge and excrement treatment, comprises sorting out organic substances of kitchen waste, sludge and excrement, dehydrating and adjusting the water content, mixing, adding fermentative bacteria, and culturing for 27 hours at 30-40 degrees C, preparing modulation agent by mixing water, sawdust or straw for removing oxidized substances, fermenting the material, heating to 50-55 degrees C from 30-40 degrees C, fermenting for 4-5 hours, stirring once in every hour, and fermenting to obtain composite soil, and sterilizing at high temperature of 90-117 degrees C.    USE - The composite soil is useful for promoting the growth and development of plants.    ADVANTAGE - The method: is safe in treating the kitchen waste, sludge and excrement; produces soil which is light weight, and has high water and air permeability performance; retains water and nutrients; contains small amount of vitamins, growth hormones and microelements, thus promoting the growth and development of plant; is simple; has high utilization rate and recycling efficiency of the wastes.    DETAILED DESCRIPTION - Preparing composite soil using kitchen waste, sludge and excrement treatment, comprises (a) sorting out organic substances of kitchen waste, sludge and excrement, (b) dehydrating and adjusting the water content of kitchen waste, sludge and excrement respectively to be 65-90 wt.%, 65-80 wt.% and 80-95 wt.%, mixing the dehydrated kitchen waste, sludge and excrement to obtain a mixed material with a solid content of 20-30%, (c) adding a fermentative bacteria, and culturing for 27 hours at 30-40 degrees C, (d) preparing modulation agent by mixing water, sawdust or straw for removing oxidized substances, (e) fermenting the material obtained in the step (d), heating to 50-55 degrees C from 30-40 degrees C, fermenting for 4-5 hours, stirring once in every hour, and fermenting to obtain composite soil, and (f) sterilizing at high temperature of 90-117 degrees C.