In order to design and analyze fast pyrolysis equipment of biomass, pyrolysis experiments of corn stalk and wheat straw were conducted by using thermogrametric analyzer. Samples were heated from ambient temperature to 500℃ at three different heating rates (5℃/min, 10℃/min, 30℃/min). Results of two biomass materials were compared and found to be similar. Derivative thermogravimetry (DTG) curves of wheat straw show that the higher the heating rate, the higher the temperature of DTG peak. A parallel-first-order reaction model was used to simulate biomass pyrolytic process. Comparison of simulation and experimental results shows that the parallel-first-order reaction model is more appropriate than simple-first-order reaction model to describe the pyrolysis of biomass in thermogrametric analyzer.