Chemical looping air separation (CLAS), which used Mn2O3/Mn3O4 as oxygen carriers, was conducted as an alternative of the conventional air separation technology. Herein, a new technique which integrated biomass gasification system with CLAS for hydrogen production was presented. Aspen Plus software combined with Fortran programing was employed to study this new system. The effects of three vital variables, including steam-to-biomass mass ratio (S/B), oxygen-to-biomass mass ratio (O/B) and steam-to-Mn2O3 molar ratio (S/M), on system performances were analyzed. The results were showed below: the mole fraction of syngas was easily affected by S/B. In term of the hydrogen yield (YH2) and thermodynamic efficiencies, they were slightly affected by S/B. As for O/B, it had a great influence on the system performance indicators. Moreover, with the increase of S/M, the temperature of reduction reactor was dropped and the remain system performances indicators were insensitive to variation of S/M. Additionally, thermodynamic performances of the researched system were evaluated. The results showed that the values of S/B, O/B and S/M were 0.12, 0.25 and 0.1, respectively, the total energy efficiency was 74.18% and exergy efficiency was 65.64%. Compared with traditional biomass gasification process, the exergy efficiency of this novel system was improved 8.62%.