In this study, ash fusion characteristics (AFC) of biomass red pine, corn straw, Bermuda grass and bamboo are investigated. Results of this study show that ash melting temperatures are higher when samples are ashed at 815 degrees C than at 600 degrees C, but the differences are small. The ash deformation temperatures of pine and straw are over 1100 degrees C, but the ash deformation temperatures of Bermuda grass and bamboo are lower than the former biomass. Also. Bermuda grass and bamboo are prone to sintering phenomenon when burning. In the thermogravimetric experiment on ash, the heating process can be divided into three stages, namely water evaporation, oxidation of organic compounds and evaporation, and reaction of inorganic components. The ash of Bermuda grass and bamboo contains more unburned organic matters because of sintering, and higher calcium content in pine ash results in a more mass loss in the third stage. The ash fusion characteristics for co-combustion of biomass with coal are investigated. It is found that the ash melting temperature firstly decreases and then increases with the content of the corn straw increase, changing as "V" shape. (C) 2011 Elsevier Ltd. All rights reserved.