The invention discloses a Belgium blackberry soil acidity biological improver and a preparation method thereof. The Belgium blackberry soil acidity biological improver is prepared by using the following raw materials, by weight, 30-40 parts of cassava residue, 20-30 parts of plant straw, 15-20 parts of a tea seed cake, 10-15 parts of vegetable leftover, 5-10 parts of soybean curb residue, 20-30 parts of modified zeolite, 5-8 parts of rice husk charcoal, 12-16 parts of sodium silicate, 14-18 parts of polyacrylamide, 5-10 parts of carboxymethylcellulose sodium, 15-25 parts of urea, 10-15 parts of calcium superphosphate, 10-15 parts of boric acid and 8-12 parts of a pyroligneous liquor. The soil improver can adjust the pH value of soil, increases organic matters in the soil, promote the microbial activities of the soil and enhance the fertilizer water penetration of the soil, has the soil improvement, water retention and drought resistance effects, has a strong bactericidal activity, and can sterilize and disinfect the soil, inhibit the growth and reproduction of harmful microbes, reduce the occurrence of soil-borne diseases and insect pests, enhance the disease resistance capability of crops, improve the blackberry output and improve the quality.