Compressive　type　accelerometers　are　widely　used　in　various　vibration　measurements.　Lead-free　piezoelectric　ceramics　as　sensitive　element　have　been　preferred　from　the　viewpoint　of　environmental　impact.　In　this　paper,　0.30　wt%　MnO-added　Bi0.485Na0.425K0.06Ba　0.03TiO3　(BNKB)　piezoelectric　ceramics　were　used　as　the　sensitive　element　in　a　compressive　type　accelerometer.　Based　on　the　finite　element　analysis,　the　influences　of　the　mass　of　the　preloading　element　and　the　thickness　of　the　sensitive　piezo-rings　on　charge　sensitivity　and　operation　frequency　were　analyzed,　thus　optimizing　the　structure　and　parameters　of　the　accelerator.　The　sensitivity　(calibrated　by　a　back-to-back　method)　of　the　accelerometer　as-fabricated　was　measured　to　be　3.9　pC/m·s-2　within　100　Hz　-　5　kHz　within　the　2dB　tolerance.　©　2011　IEEE.