As a renewable resource, Pinyon pine can be converted into bio-oil, gas, and char through pyrolysis. It is known that recycling of the non-condensable gases, which are produced by fast pyrolysis, can increase liquid yield and decrease char yield. In this study, pyrolysis characteristics and kinetics of Pinyon pine were investigated in TGA using simulated non-condensable gases (N-2, H-2/N-2, H-2/CO2, and He/CO/H-2). The apparent activation energy of Pinyon pine increased from 43.9 to 160.3 kJ mol(-1) with increasing pyrolysis conversion from 5% to 95% in pure nitrogen, and reaction order was 1.35. When hydrogen (H-2) and carbon monoxide (CO) mixtures were used as simulated gases, the maximum degradation temperature and activation energy decreased by 4-11 degrees C and 6.1-10.2 kJ/mol, respectively. The results show that recycling of non-condensable gases could positively influence the fast pyrolysis of biomass. (C) 2014 Elsevier Ltd. All rights reserved.