A new experimental system is presented to make hydrogen by hydrolyzing Zn nano-particles in a cyclone reactor, in which the chemical reaction and gas-solid separation are carried out simultaneously. The gas-solid form a three-dimensional, turbulent flow-field induced by strong revolving force. The turbulent moving improves the efficiency of heat and mass transfer, which is favorable to chemical reaction. And the Zn nano-particles of 10-20nm preheated at about 523K can react with water steam rapidly. XRD and TEM analysis shows that the solid product consists of ZnO and Zn and has a blended morphology of nano-rods and nano-flakes. The gas-solid separation efficiency primarily depends on the inlet velocity when the particle size distribution is determined, and the particle resident time in the reactor has close relation to Reynolds number of gas inlet. It is confirmed that the steam inlet velocity of 10m/s and Ar inlet velocity of 5m/s are favorable.