The invention discloses a cold charging production process of high-compactness and high-purity fine-grain grinding ball steel. The cold charging production process comprises the following processes ofpre-desulfurizing molten iron, smelting in a converter, refining in an LF furnace, carrying out RH vacuum treatment, continuously casting, slowly cooling a large round billet casting blank, heating,rolling, cooling, high-temperature pit entering slow cooling, pit exiting finishing, packaging and warehousing. According to the production process, a grinding ball steel round billet cold charging temperature control system is adopted for heating, and a mode of combining differential temperature rolling and single-pass high-pressure rolling is adopted, so that the deformation of the center of thebillet is increased, and the internal compactness and the grain size of the steel are improved. The grinding ball steel produced by the production process has the advantages of excellent macrostructure (central porosity is less than or equal to 1.0 grade and general porosity is less than or equal to 0.5 grade), high purity (A-type inclusions are less than or equal to 1.0 grade, B-type inclusionsare less than or equal to 0.5 grade, C-type inclusions are less than or equal to 0.5 grade and D-type inclusions are less than or equal to 1.0 grade) and fine austenite grains (austenite grain size isgreater than or equal to 6.5 grade). The grinding ball obtained by carrying out a conventional rolling process on the produced grinding ball steel is good in impact toughness and long in fatigue life.