A mirabegron slow-release mini-pill includes a drug-containing mini-pill and a coating layer, the drug-containing mini-pill is coated with the coating layer, the drug-containing mini-pill comprises 25mg of mirabegron, 70mg of a blank pill core, 100-200mg of a filler, 50-150mg of a lubricant and 5-50mg of a binder, the coating layer comprises 35-175mg of Eudragit NE30D and 5-52mg of talc powder, preparation steps are as follows: 1, preparing materials; 2, mixing; 3, preparing the binder; 4, pelleting; 5, preparing a coating agent; 6, coating; 7, filling; and 8, aluminum molding and finishing. The mirabegron slow-release mini-pill is used for urge urinary incontinence, dibetes insipidus overactive bladder, two advanced technologies of a novel slow-release preparation and a mini-pill preparation are used, treatment effect is stable, bioavailability is higher, the mirabegron slow-release mini-pill has the advantages of good drug stability, convenient packaging, transportation, storage and the like, and the preparation method is simple and suitable for industrial production.