Abstract: For the industrial fluidized bed gas-phase polyethylene production process, a new technology that produces bimodal polyethylene in a single reactor by oscillating the operation parameters was proposed.The change of molecular weight distribution during oscillation of operation parameters, including hydrogen flow rate, ethylene flow rate, comonomer flow rate and reaction temperature was investigated by simulation.After oscillating the operation parameters, the bimodal molecular weight distribution (MWD) of polyethylene was generated.The simulation results show that it is feasible to produce bimodal polyethylene in a single reactor by oscillating the operation parameters.The simulation result also shows that oscillating hydrogen flow rate is the most effective method to produce bimodal polyethylene.