The invention relates to the technical field of fertilizers and particularly relates to a special fertilizer for selenium-enriched litchis and a preparation method thereof. The special fertilizer for the selenium-enriched litchis is prepared from the following raw materials: farmyard manure, biogas residue, donkey bone meal, corncobs, bagasse, lotus seed heads, rice straws, tea tree sawdust, cotton seed hulls, fruit peels, wheat bran, watermelon seeds, sesame seed shells, gypsum powder, grape sugar, garlic juice and a decay promoter. According to the special fertilizer for the selenium-enriched litchis, the source of the raw materials is wide, no chemical synthetics is added, the preparation process is simple, the prepared fertilizer is environmentally friendly and can be used for providing sufficient elements such as nitrogen, phosphorus and potassium for litchi growth, so that the litchis are high in selenium content, good in taste and better in overall quality.