The invention discloses a multifunctional ecological acid soil amendment. The multifunctional ecological acid soil amendment is prepared from the following raw materials in parts by weight: 25-79.9 parts of silkworm dropping, 10-40 parts of tobacco stem, 0.1-1 part of sodium alginate, and 10-34 parts of bovine-derived powder. The soil amendment has the efficacy of increasing soil pH value, reducing toxicity of heavy metal on crops, increasing soil organic matter content, freeing soil, improving soil fertility, avoiding underground pest and threadworm, reducing pesticide consumption on the soil, improving soil ecological environment, and the like, and has a wide application prospect.