Abstract: A lot of fine suspended zirconium particles can develop to become a range of flame when zirconium dust cloud burns. Zirconium powder material was widely applied as a kind of high energy fuel. Dust cloud transient flame propagation experimental system was used to study the characteristics of flame propagation speed of zirconium metal dust cloud in a vertical pipeline, and a combustion model of zirconium particles moving upward in the pipeline was established. The results show that zirconium dioxide particles have two kinds of crystal phase-monoclinic crystal phase and tetragonal crystal phase. The zirconium dust cloud concentration is high or low which can be judged preliminarily according to the initial shape of the flame fronts. The maximum flame propagation speed of zirconium powder cloud first increase then decrease with the increasing zirconium dust cloud concentration, because the oxygen in the pipeline is not enough as result of rich fuel combustion and the heat energy are absorbed by the unburned particles. When the zirconium dust cloud concentration is 0.625 kg/m³, the fastest flame propagation speed in the pipeline is up to 39.7 m/s. In addition, a combustion model of zirconium particles moving upward in the pipeline was established, the whole combustion process was divided into four stages. The flame propagation process of zirconium dust cloud in vertical pipeline are characterized from macro phenomenon and the micro mechanism.