The invention discloses soil continuous cropping protector and a preparation method and application thereof. The soil continuous cropping protector is made from, by weight percent, 30-50% of biological agent and 50-70% of silica solution. The biological agent is made from, by weight, 30-35 parts of chrysanthemum flower, 15-25 parts of fig, 30-35 parts of tea fruit, 5-10 parts of Chinese date, and 5-10 parts of licorice root. The silica solution is 35-45% in mass concentration, and 3.0-3.4 in modulus. The silica solution enables massively accumulated heavy metals in soil, such as cadmium, mercury, lead and arsenic, to be nonionic by replacement reaction, and pollution of crops by the heavy metals in the soil is eliminated or relieved. By the soil continuous cropping protector, soil quartz structure is changed, acid-base balance of the soil is corrected, soil basicity is improved, disintegration of organic fertilizers is promoted, soil pathogenic bacteria are inhibited, and the problems of soil continuous cropping obstacles and the like are solved basically.