The invention discloses a processing method of slag chili, which belongs to the technical field of agricultural product processing. The slag chili is processed by mixing corn powder, fresh chili, salt vegetables, plant oil, salt, pepper, ginger, black pepper, mushrooms, garlic and monosodium glutamate. The processing method has the beneficial effects that the burdening with various flavors is added to the raw materials; during the processing, firstly, the fresh chili is prepared into peppery slurry, secondly, the peppery slurry, the corn powder and the salt vegetable are mixed and then loaded into a jar, and finally, the jar is inverted and subjected to water seal, so that the slag chili is moistened by water vapor and better alcoholized and has not only deliciousness and tastiness of the corn powder, but also mellow flavor of the salt vegetables; after the slag chili is steamed in clear soup, the flavor of the slag chili is more thorough and durable; and after the slag chili is fried through the plant oil and spices step by step, the taste of the slag chili is more charming and strong, and the slag chili is spicy and sweet and has a special cool flavor. The processing method is suitable for large-scale industrial production, and can meet the requirement of people on food diversification.