Abstract: 2,5-diketopiperazine (DKPs) was selected as N-containing model compound to investigate fuel-N conversion pathway during straw pyrolysis. The experiments were conducted using a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer (TG-FTIR) in Ar atmosphere. The results show that NH₃, HCN and HNCO are the major N-containing species during DKPs pyrolysis at 20, 40 and 60℃/min. The yield of NH₃ is the largest, followed by HCN and the amount of HNCO is the lowest. With increase of heating rate, the weight loss curve moves to right and the yields of HNCO and HCN increase, while that of NH₃ decreases. K, Ca and Fe have a catalytic effect on nitrogen conversion during DKPs pyrolysis. In the presence of K and Ca, the formation of NH₃ and HCN is enhanced. Fe can promote the formation of NH₃, but inhibit the formation HCN.