Abstract: was carried out using thermogravimetric analysis with washing and salt adding samples. The original sample was washed with 5% acids (H2SO4, HCl) and distilled water, respectively. Inorganic compounds in pretreated samples were examined with ICP-AES. The catalysis effects of alkaline compounds on pyrolysis characteristics of original and pretreated biomass were analyzed with K2CO3 and dolomite (CaCO3·MgCO3) addition. The results show that acid wash can decrease the concentration of alkaline cations in biomass, enhance the mass loss rate of biomass pyrolysis, and shifts the pyrolysis to higher temperature. Alkaline compounds addition can promote biomass pyrolysis at lower temperature.