42.6%、86.2%、92.1%。Exergy analysis is a kind of scientific and comprehensive energy analysis method. By making positive and negative thermal balance analysis on new type Ⅱ biomass briquette hot-water boiler, we got the conclusion that the largest exergy loss lies on irreversible burning which reaches 69.93%, and irreversible heat transfer exergy losses follows, reaches 14.5%, then the calculation results were analyzed using the concept of avoidable exergy loss, the results show that the position of combustion, the position of heat transfer, the position of smoke and the practical efficiency of the exergy are respectively 42.6%,86.2%,and 92.1% after adopting the concept of avoidable exergy loss.