The invention relates to an ecological high-ductility cement-based composite material prepared from organic wastes, and a preparation method thereof. The cement-based composite material comprises, bymass, 100 parts of cement, 50-67 parts of fly ash, 42-50 parts of water, 10-40 parts of fine sands, 10-50 parts of organic wastes, 0.3-0.8 part of a water reducer, 0.1-0.13 part of a viscosity regulator and 2.6-3.4 parts of fibers. The preparation method comprises the following steps: carrying out dry mixing the cement, fly ash, the water reducer, the viscosity regulator, the fine sands and the organic wastes in a stirrer for 1-2 min; adding water, stirring the obtained mixture and water for 3-4 min; adding the fibers, stirring the obtained mixture and the fibers for 2-3 min; and filling a diewith the finally obtained mixture, carrying out die stripping after the plasticity is completely lost, and carrying out standard curing for 28 days or 60 DEG C steam curing for 3 days. The low-cost ecological high-ductility cement-based composite material prepared from organic wastes has great application prospect in engineering, solves a problem that the wastes cannot be processed or are improper to process, and has protruding technologic, ecologic and environmentally-friendly benefits.