Abstract: In order to understand the effects of alkali and alkaline earth metals(AAEM) on the pyrolysis characteristics of biomass, microcrystalline cellulose(Mcc) loaded K,Na,Mg,Ca with different concentrations were investigated by thermogravimetric analysis and tubular furnace. The results indicated that AAEM could catalyze pyrolysis process, increase the char yields markedly, shift the pyrolysis process to lower temperature, reduce the activation energy for pyrolysis, decrease CO and C2 content and increase CO2 and CH4 in produced gas. The catalysis of the metal added on the cellulose was K>Na>Mg, Ca. The catalysis of metal Chloride (MCl) was relatively weak compared to CH3COOM, and the catalysis was limited when the added concentration of MCl was low. CH3COOM addition affected pyrolysis temperature and production of cellulose remarkably, separated the pyrolysis into two process, and increased H2 content in produced gas. The organically bound alkali metals may catalyze pyrolysis of biomass more than the inorganically alkalis in biomass. The characteristic and production distribution of biomass pyrolysis is affected by AAEM species and forms.