The invention discloses a dewatering water advanced treatment softening system and process. The process flow comprises the following steps: dewatering water from a mine, crystallizing and granulatinga fluidized bed, carrying out solid-liquid separation on the fluidized bed, and cleaning with a clean water tank. After being softened by the process, the total hardness of the water is effectively removed, the removal rate reaches 90%, the effluent turbidity is less than 5NTU, and the inflow requirement of the subsequent pre-desalination process is met. The system is high in equipment operation load, small in occupied area, compact in arrangement, easy to operate and adjust, stable in effluent quality, low in maintenance workload and high in automation degree. Compared with a traditional limeand soda ash softening process, the process has the advantages that the occupied area of a lime storage room is reduced, and the common problem of excessive addition of chemicals in lime treatment issolved; the problems of powder leakage, blockage and the like in the lime milk preparation process are eliminated, the operation site is pollution-free, and the management is convenient; calcium carbonate particles generated by crystallization and granulation can be recycled in a desulfurization system, so that the sludge output of the system is greatly reduced, and the operation cost is relatively low.