Abstract: According to the speciality of biomass briquette combustion, thermodynamic calculating and special processing methods, the special boiler which applies biomass briquettes was designed and made. It had double fire grates which have function of smoke removing. Moreover, the combustion effiency of this boiler was higher and the incomplete combustion loss of solid and gas was less. The contents of fume, nitrogen oxide and sulfun dioxide in the vent smoke were low enough to achieve the national standard. So it would have a splendid future to use straw as the substitute of coal in China.