Petroleum resin is used in industrial applications. It has a tackifying effect and is suitable for use in paint, printing ink, adhesives, rubber and other areas where tackiness is required. It is a kind of thermal plasticizing hydrocarbon resin produced by C5, C9 fraction, by-products of petroleum cracking, through pretreatment, polymerization and distillation. It is not a high polymer but a low polymer with the molecular weight between 300-3000. Featured by acid value, easy mutual solubilities, resistant to water, resistant to ethanol and chemicals. It has the chemical stabilizing property to acid and alkaline, viscosity adjusting and thermal stabilizing, C5/C9 Copolymerized Petroleum Resins can be used in hot melt adhesives, adhesives, rubber and tire fields especially in radial tire with the effects of not only increasing adhesion between particles but also improving adhesion between particles and cord; in hot melt adhesives, adhesives fields, C5/C9 can not only provide better initial cohesiveness, but can also be used like rosin resins to adjust and improve viscosity durability and strength of mixture of glue and resins.