As the core unit of delayed coking instrument in the petrochemical industry, the gasifier became the restrictive factors of production and capacity in improvement of the whole process Due to the poor environment conditions of high temperature, the corrosion wearing of the refractory brick in the gasifier is comparatively severe. In order to ensure the safety of production equipment, the complicated maintenance work for the refractory brick of the gasifier is needed Geometry measurement on inner surface must be completed regularly as an example, the thickness of the refractory brick in Take Texaco gasifier