The present invention relates to technology of metallurgical slag processing, in particular to a technological method of ladle slag thermal processing. The technological method of the ladle slag thermal processing comprises the following steps that: ladle molten slag enters a roller slag falling area from a funnel, the slag falling area is provided with a steel ball inside, the steel ball rotates with a roller, the molten slag is cooled by the steel ball, the heat of molten steel and the slag is quickly taken by the steel ball, the molten steel and the slag are taken to a water cooling area by the rolling steel ball after being plasticized and solidified, the molten slag and the steel ball are synchronously cooled by water and then discharged to an outer roller body through a lattice type grate bar of the roller, and the molten slag is cooled again by water in the outer roller body and discharged out finally, wherein the slag and steel are separated under the action of the steel ball rolling at a high speed. The technological method can safely, environmentally and rapidly process the high-temperature ladle slag, can achieve the separation of the slag and the steel, and can solve the problem of processing the ladle slag.