The segregation of a larger and smaller particles in a gas solid fluidized bed packed with open ended screen cylinders was studied with Han River beach sand. The overall degree of segregation was defined as the difference in the weight percent of smaller particles between the samples of top and bottom of the bed, while the local degree of segregation was defined as the local weight percent of the smaller particles. The experiment was started after putting larger particles on the top of the smaller one. The local and the overall degree of segregations as a function of bed height were obtained for the various gas flow rates, sizes and times. As a result, the screen-cylinder packed fluidized bed could be effectively used for the particle segregation. Also, the higher bed height gave better segregation and the segregation was most effective at 1.4 times gas flow rate of the minimum fluidization.