The invention provides a low-heat and high-ductility cement-based composite material, which is prepared from the following raw materials in parts by weight: 15-75 parts of cement, 0-80 parts of mineral admixture, 0-50 parts of fine aggregate, 8-25 parts of water, 0.6-2.5 parts of fiber and 0.25-2 parts of an admixture, wherein the cement is high belite cement. The high-ductility cement-based composite material provided by the invention is low in hydration heat and good in tensile property. The invention also provides a preparation method of the high-ductility cement-based composite material.