The invention discloses an environment-friendly light porous simulated soil cultivation medium body and a preparation method thereof. The cultivation medium body is of a continuous integrated porous simulated soil sponge structure and is prepared from 1-10 parts by weight of polyurethane binding body, 1-50 parts by weight of filler, 0.01-50 parts by weight of auxiliary material and 0-5 parts by weight of embedded functional matter. The filler is at least one of organic filler, inorganic filler and organic and inorganic composite filler. The auxiliary material is a mixture of at least two of a surface active agent, a catalyst, a chain extender, a fire retardant and a foaming agent. The embedded functional matter is at least one of plant seeds, a rooting agent, a soil sanitizer, a straw fermenting agent, potash fertilizer, phosphatic fertilizer, nitrogenous fertilizer and compound fertilizer. The prepared simulated soil cultivation medium body is low in weight, high in aperture ratio, good in hydrophilia and water retention performance and excellent in mechanical property, and can be applied to the fields of vertical greening, roof greening, urban landscaping, indoor greening, intelligent greening, slope restoration, gardens and horticulture, ecological remediation, ecological management, soilless culture and the like.