The classification method of steel barrel by inner wall type was proposed. The performance characteristics of commonly used materials of inner spray coat were discussed. The production process of inner spray coat steel barrel was summarized on the basis of production practice. On the basis of hatch type and material thickness, steel barrels were classified according to materials and types of the inner wall. The performance characteristics of inner spray coat materials were listed through comparison. The production process of steel barrel with inner spray coat was summarized according to process flowsheet and the key points of process were proposed. The third classification method of steel barrel was defined by distinguishing inner wall materials, inner soft liner or direct contact. Epoxy resin, PTFE and phenol aldehyde resin were commonly used inner wall materials in China. The mature process flowsheet of inner spray coating was as follow: de-oil of surface, phosphorization of surface, drying, spraying, plasticizing through baking, and quality detection of coating surface.