BiFeO3 (BFO) thin films produced with varied film thicknesses ranging from 100 to 230 nm were fabricated on BaPbO3(BPO)/Pt/Ti/SiOx/Si substrates by rf-magnetron sputtering. Saturated polarization-electrical field hysteresis loops, polarization response by pulse measurement, and retention properties were obtained for BFO films with various thicknesses on BPO. The retention behaviors of BFO demonstrate logarithmic time dependence and stretched exponential law. When the thicknesses of BFO films increase, the contribution of logarithmic time dependence to retention, the stretched exponential law becomes dominant. BFO films with thinner thickness exhibit better retention properties but possess smaller remnant polarization.