Research on fluoride emission from coal combustion is important to solve a serious fluoride pollution problem. Occurrence mode and behaviors of fluoride during coal combustion were investigated. XRD and XPS analysis showed that fluorides in chinese coal existed mainly as -CF2-, muscovite and apatite. Coal pyrolysis and combustion were carried out by TG-MS. HF was found to be released from both coal pyrolysis and combustion. Experimental result under different combustion conditions showed that fluoride content in flue gas and particles increased with increase in oxygen concentration or temperature, while fluoride content in residue decreased with it.