In this paper, many rules about N2O and NOx, emission under fluidized bed combustion conditions were found by experiments. The research results indicate that CaO, CaSO4, Fe2O3 and char have important influence on decomposition of N2O; co-combustion of coal and biomass are effective measures to low N2O and NOx emission. (C) 2002 Published by Elsevier Science B.V.