Abstract: n-Heptane is the most important straight chain paraffin in the fossil-fuel industry. In this work, pyrolysis behavior of n-heptane at high temperature is investigated by a se-ries of ReaxFF based reactive molecular dynamics simulations. Temperature effects on then-heptane pyrolysis and related products distributions have been detailedly analyzed. The simulation results indicate that the temperature effect is characterized in stages. High tem-perature can accelerate the decomposition of n-heptane, but the influence becomes small after it reaches a certain level. According to the different reaction behaviors, pyrolysis of n-heptane could be divided into three stages. The variation trends of the mass fraction evolu-tion of ethylene (C₂H₄), C3, and C4 calculated from reactive molecular dynamics simulations are in good agreement with the previous experimental results. The apparent activation en-ergy extracted from the first-order kinetic analysis is 53.96 kcal/mol and a pre-exponential factor is 55.34×10¹³ s^-1, which is reasonably consistent with the experimental results.