With Aspen Plus software, the simulation of the whole process of bio-syngas production from gasification via pressurized interconnected fluidized beds was carried out, and the model was validated by the comparison of simulation results and experimental results. The effects of gasification temperature (Tg), gasification pressure (pg) and steam to biomass ratio (S/B) on bio-syngas composition, H2/CO ratio, gasification proportion, bio-syngas yield, and carbon conversion were studied. The results showed that gasification temperature, gasification pressure and S/B had great influences on the biomass gasification process and the suitable gasification temperature and pressure was around 800℃ and 0.4MPa.