The invention discloses a production process for converting gray black barite into a white barite finished product. The process flow comprises: crushing black barite raw ore, roasting, grinding into powder, washing with water, pickling overflow liquid obtained after washing with water, rinsing, filtering, drying, finely breaking, packing and obtaining finished product, wherein the bottomflow liquid obtained after washing with water is filtered, the product obtained is dried and finely ground, and the ground product is packed and thus, the drilling fluid finished product is obtained. When the production process is used, gray black barite can be converted into white barite which can be directly used in paint making, coating, paper making and the like industries as a filler, the density of barite can be increased greatly, the corresponding indexes such as alkali metal content and viscous effect can be improved correspondingly, the prepared drilling fluid weighting agent can meet high-density and high-quality drilling fluid requirements, the application range of the gray black barite can be obviously expanded and the utilization value of the gray black barite can be increased.