Abstract: The generation mechanism of carburizing IGO is described. At the same time, the IGO problem of 18CrNiMo7-6 alloy carburizing steel is analyzed and studied by using the box controlled atmosphere carburizing furnace, and the carburizing process is studied and optimized. The technological parameters and capability of carburizing process were analyzed by experiments. The results show that under the condition of the workpiece material and the depth of the cementing layer, the strong carburizing potential is divided into 1.15% and 1.1%, and the carbon potential slow drop section is added between the two sections, while the diffusion carbon potential is increased to 0.82%, and the carbon potential slow drop section is also added to avoid the air inlet during the carbon potential drop process, this can effectively reduce the generation of IGO.