Abstract: HZSM-5 is modified by Dawson-type phospho-wolframic（PW）acid,and the effects of PW loading on the weight-loss characteristics and reaction kinetics parameters of biomass pyrolysis are analyzed. Besides,the yield and moisture content of liquid and the organic phase composition is detected. The results show that the addition of HZSM-5 make the thermo-gravimetric curves shifted to the low-temperature side. However,with the increase of PW loading,the curves gradually are shifted back to the high-temperature side,and the maximum weight-loss rate decrease. The reaction order increases from 1.97 to 2.12,the activation energy decreases from 53.32 kJ/mol to 31.15 kJ/mol,and the frequency factor decreased from 8.27×10~4 s^-1 to 9.61×10~2 s^-1,indicating that the complexity of the conversion process increases and the severity decreases. The 10%PW/HZSM-5 catalysis decreases organic phase yield to 10.73 %,but increases high heating value to 38.01 MJ/kg,and promotes the content of I-type mono-aromatic hydrocarbons to 52.29 %. Besides,the content of polycyclic aromatic hydrocarbons is only 12.32%,and it shows a higher selectivity for BTEX. When the PW loading is increased to 20%,the hydrocarbon composition deteriorates slightly,and the conversion degree of oxygen-containing organics decreases.