Abstract: The use of the new type cheap inorganic insulation, non-fire-retardant insulation materials was one of future heat insulation and cooling research directions in heat harmful mines. In this paper, it took the vermiculite mortar insulation materials as the example, studied the material composition morphology and performance under optimal ratio. Combined with the site engineering applications of track cross-cut in heat harmful mines, it obtained that the vermiculite mortar spray on the surface of the injection could effectively reduce the airflow warming magnitude. When the sprayed layer thickness of vermiculite mortar was 6 cm, the airflow warming magnitude was smallest, and the results were best.