This paper presents the total dose radiation performance of 0.8μm SOI CMOS devices fabricated with full dose SIMOX technology. The radiation performance is characterized by threshold voltage shifts and leakage currents of transistors and standby currents of ASIC as functions of the total dose up to 500krad（Si）. The experimental results show that the worst case threshold voltage shifts of front channels are less than 320mV for pMOS transistors under off-gate radiation bias at 1Mrad（Si） and less than 120mV for nMOS transistors under on-gate radiation bias. No significant radiation-induced leakage current is observed in transistors to 1Mrad （Si）. The standby currents of ASIC are less than the specification of 5μA over the total dose range of 500krad（Si）.
