The present study has been conducted on three dimensional flow characteristics between poly-silicon particles and gas in a large scale fluidization bed reactor (FBR). This study was mainly performed numerically by commercial code Fluent. The Eulerian multiphase model was used to simulate hydrodynamics of bubbling fluidized bed. The size of silicon particle was 1000 μm and 2000 μm, and density was 2329 kg/m3. The reactor chamber had base gas flow from bottom porous plate and reacting flow from the jet nozzles (single or multi) with high velocity. The base gas and reacting gas were hydrogen (H2) and trichloro-silane (TCS) respectively. The TCS mole fraction was controlled to 13% and 20% of total gas amount. From the simulation, performance and design parameters were evaluated on single and multi nozzles jet related to flow mixing characteristics and a gas-solid contact performance. As a result, considering of the mixing characteristics between the gas and the solid, multi nozzle jets much improved the mixing performance in the reacting zone. In addition, the widespread distribution of TCS which led to better gas-solid contact performance were showed by the multi nozzle jets. This CFD data will provide useful basis to predict fluidization characteristics in the poly-silicon FBR process.