The invention discloses a process for preparing industrial oil and relates to the technical field of industrial oil preparation. The method includes the steps of preparing of dehydrated mineral oil, preparing of mixed material liquid A, filtering and obtainment of finished products. The method for preparing industrial oil is easy and convenient to implement, the produced products are good in quality, the production cost is saved, it is avoided that titanium dioxide is wasted as industrial waste residues, more importantly, raw materials are reused, so that the pollution to the environment is avoided, good social benefits are achieved three-waste treatment, and meanwhile, certain economic benefits are achieved; the utilization rate of industrial oil is increased greatly, the energy saving and environment protection requirements of the industrial field in China are met, the requirement for resource saving is met, raw materials are wide in source, and the method is wide in industrial use range, great in future development and good in development prospect.