SrBi2Ta2O9 (SBT) thin films were deposited on (111) oriented Pt bottom electrodes using the rf magnetron sputtering method and then postannealed at 650-800 degrees C for 30 min in different oxygen atmospheres. The effect of Bi content on the c-axis preferred oriented growth was confirmed by the control of the Bi2O3 loss during the postannealing. With increasing Bi content in SBT thin films, the degree of the c-axis preferred orientation was enhanced. In addition, a bimodal grain size distribution due to the Sr deficiency in the SBT film was observed. It is suggested that the c-axis preferred oriented growth on Pt(111) bottom electrodes can be attributed to growth controlled by surface energy minimization.