Solid raw materials in form of powder are sieved and premixed, then stored in respective silos. The solid materials are weighed accurately by dosing belts according to the detergent powder formulation, and fed to the agglomerator. While the liquid raw materials are dosed accurately by dosing pumps and fed the agglomerator in form of sprayed particles. The agglomeration product from its bottom is fed to a fluidizing bed to remove free water in the particle's surface and form crystal water in the powder to increase its added value. Perfume, enzyme and other minor ingredients are added into this powder in post-addition unit to obtain final high-grade product with bulk density of 0.45 to 0.8 kg/L, waiting to be packed.