The invention relates to a seed cladding material for planting in salt and alkali and desert soil, and a biological conversation vegetative body prepared by utilizing the seed cladding material, belonging to the technical field of agricultural production. The seed cladding material is prepared by mixing and fermenting crushed straws, humic acid, amino acid, bean pulp, diatomaceous earth, bone meal, magnesium sulfate, zinc sulfate, ferrous sulfate, borax and organic selenium. The biological conversation vegetative body is prepared by comprising the following steps: producing the cladding materials into a tube body, mixing plant seeds with a seedling culturing matrix, filling to the tubular cladding material, and then sealing the two ends of the tube body with the cladding materials. In sowing, a farmland is furrowed, then the tubular biological conversation vegetative bodies are put in the furrows end to end and are covered with soil in a dry farmland, then watering is performed thoroughly, and irrigation is directly performed to the paddy fields. After the biological conversation vegetative bodies absorb water fully, seeds start sprouting and growing in the seedling cultivating matrix in the tube bodies and get out of the tube bodies, and then the tube body cladding materials are gradually decomposed and diffused around the roots of seedlings, so that crops can always absorb nutrients of the tube body cladding materials at the earlier stage of growing. The seed cladding material and the biological conversation vegetative body are especially suitable for salt and alkali and desert soil.