The utility model discloses an additive stable dispersion auto-weighing adding system which comprises two mixing tanks communicated with a measuring tank, wherein the mixing tanks are communicated with a water tank; a stirrer is arranged in each mixing tank; a first valve is arranged between the first mixing tank and the measuring tank; the second mixing tank is connected with a three-way valve through a circulating pump to form a cycle; the other path of the three-way valve is communicated with the measuring tank; the water tank is communicated with a pipeline between the three-way valve and the measuring tank through a pipeline and a second valve; the measuring tank is communicated with an intermediate storage tank through a pipeline and a third valve; and the intermediate storage tank is communicated with a concentration tank through a pipeline and a fourth valve. Through the utility model, the additive can be effectively dispersed more uniformly, and precipitates are not easily generated; and tiny particles formed by the additive are reduced, and the consumption of the additive is reduced, so that the additive can be uniformly dispersed into a product and the intrinsic performance of the product is improved.