The invention discloses a water prevention and control process in construction of a metallurgical underground mining ore pass fragmenting system, and belongs to the technical field of underground metal mine water prevention and control methods. According to the technical scheme, grouting curtain construction is conducted on an upper ore storage bin, a jack shaft, a smashing chamber, a lower ore storage bin, a belt ore supply chamber and the like, through the direction-fixed branch hole construction technology and the less-footage more-punching method, the utilization efficiency and exposing rate of grouting holes are increased, and therefore the optimal grouting effect is achieved; meanwhile, ground pre-grouting construction is conducted on the ore pass fragmenting system in the shaft excavation period, the construction period can be saved, and the construction safety in the digging process is ensured. The situation that in the construction of a traditional ore pass fragmenting system, the water control concept is detected through working face grouting is broken through, and a new concept is provided for water prevention and control of large modern metallurgical mines with complex hydrogeological conditions. The water prevention and control period in the mine construction can be remarkably shortened, the safety coefficient in the construction process is increased, engineering investment is reduced, and the construction speed is increased.