Abstract: The biomass consists of three main components: cellulose, hemicellulose and lignin. The alkali metal salt plays a different catalytic role during the three components pyrolysis. In this paper, the effect of K₂CO₃ on releasing characteristics of gaseous products during straw and its three components pyrolysis at 550～750℃ was studied by using microfluidic bed reactor（MFBR）. The kinetic parameters of each gaseous product were obtained by isothermal model integration method. The results show that during the three components pyrolysis, at low temperature, the addition of K₂CO₃ promoted the conversion rate of CO and CO₂, while the conversion rate of CO and CO₂ decreases at high temperature. In addition, the releasing characteristics of gaseous products for straw is slightly different from those of the three components, indicating that there is an interaction between the three components, which affects the overall reaction. Besides, it was found that K₂CO₃ had different effects on the activation energy for each gaseous product, which confirmed that the formation mechanism of different gaseous products was different.