A biological slow-release fertilizer for fleece-flower root comprises urea, potassium polyphosphate, ammonium polyphosphate, magnesium sulfate, calcium chloride, trace elements, tea saponin, plant oilbran cake, fermented manure fertilizer and bentonite. By self-made potassium polyphosphate and ammonium polyphosphate, slow-release effect and bio-fertilizer effect are effectively provided. After application of the biological slow-release fertilizer for fleece-flower root, topdressing is not required, and yield of fleece-flower root can be effectively increased and prevalence rate of fleece-flower root can be reduced.