Mercury is a major concern among hazardous heavy metals because of its high volatility and high toxicity, and coal combustion is recognized as one of the main anthropogenic sources of this element. Various products from a coal preparation plant in Tianzhuang, Henan Province, China, were used to study the mercury emission behavior during combustion. The results indicated that the mercuric inorganic compound has been enriched to the middling coals by physical separation methods. Further studies showed that the raw, middling, and clean coals had similar mercury emission behavior during combustion. The elemental mercury is the main form in smoke at various combustion stages.