Oxide-carbon refractories, usually using phenolic resin as a binder, have been widely applied in metallurgical industry. Their firing has important effect on the properties, such as strength, porosity and thermal stability of the binder. Main processes occurring during the firing have been investigated. Below 750°C, the binder decomposition was the main process. Its critical range was 400–600°C, lots of functional groups decomposed, which caused a large amount of volatiles generated and many pores formed, leading to a fast decreasing of the strength by 50.1%. Above 750°C, the binder shrinkage was the main process. At 750–800°C, the crystallite size of the binder increased greatly, causing a rapid shrinkage and a fast decreasing of the porosity, which resulted in a significant increasing of the strength by 11.0%. As the temperature increased up to 950°C, the shrinkage became slow, which leaded to that the porosity decreased slowly and the strength kept almost constant, implying that the thermal stability was good. Therefore, a slow heating rate was needed at 400–600°C and 750–800°C, and the firing temperature should exceed 800°C.