The invention relates to a flocculating agent premixing device of a washing machine. The flocculating agent premixing device comprises a premixing cavity. A stirring wheel is arranged inside the premixing cavity. Inflow water of the premixing cavity drives the stirring wheel to rotate to stir and premix a flocculating agent solvent inside the cavity. Due to the arrangement, the stirring structure is driven by the inflow water to rotate, the structure of the premixing structure is simplified, and the production cost is reduced. Meanwhile, the invention further relates to a washing machine applying the flocculating agent premixing device. The flocculating agent is diluted into a solvent of the set concentration by the premixing device in advance and then put into the washing machine, so that the put flocculating agent is more uniformly distributed in a flocculation cylinder, the flocculation reaction time is shortened, and the purpose of improving the flocculation efficiency is achieved. Meanwhile, the flocculating agent premixing device is simple in structure, remarkable in effect and suitable for being applied and popularized.