The invention relates to a biological fermentation composition with an anti-cancer effect. The biological fermentation composition is prepared by using a method comprising the following steps: a, preparing a culture medium mixed solution; b, sterilizing; c, cooling; d, inoculating to obtain a fermentation solution; and e, standing to obtain the biological fermentation composition with the anti-cancer effect. The composition disclosed by the invention can be used for improving the in-vivo micro-ecological environment, balancing and regulating effective microbial communities in intestinal canals, repairing damaged cells, replenishing various in-vivo active bio-enzymes, amino acids, nucleic acids, trace elements and the like, improving the immunity of a human body, preventing diseases, effectively inhibiting cancer cells and stopping the dispersion and development of the cancer cells. Meanwhile, the biological fermentation composition can be used for improving an acidic physique to be a weak alkaline physique, is particularly suitable for the cancer crowd, the crowd with hypertension, hyperlipidemia and hyperglycemia and the fat crowd, can be prepared into various dosage forms such as pills, paste, aqueous solutions and the like, and has favorable supportive therapeutic effects on cancer, diabetes, digestive system diseases and the like.