The catalytic effect of HZSM-5 on fast pyrolysis of lignin was investigated by using an analytical pyrolyzer coupled with Gas Chromatography and Mass Spectrometry (Py-GC/MS). The distribution of products was studied primarily obtained at different reaction conditions of temperature and addition ratio of HZSM-5. The main products were phenols and aromatic hydrocarbons. With the addition of HZSM-5, the content of phenols was decreased from 67.66% (for pure lignin) to 26.07%, and the content of aromatic hydrocarbons was increased from 10.77% to 57.38% when the mass ratio of HZSM-5: lignin was 1:1. However, the effect of temperature on the reaction activity of HZSM-5 in the range of 400-600°C was not significant. It was concluded that the addition of HZSM-5 enhanced the conversion of phenols to aromatic hydrocarbons by deoxygenation, and this effect was improved with the addition ratio of HZSM-5 increasing.