Total dose effects on SiGe-on-SOI HBT were studied using semiconductor device simulation tools. STI and EB spacer oxide trap charges and interface trap charges cause additional base leakage current, leading to degradation of electrical parameters in SiGe-on-SOI HBT devices. The excess base currents and normalized current gain under different bias conditions and low-temperature conditions were analyzed. The results show that the degradation at cutoff bias is the worst, followed by zero bias, while forward bias and saturation bias exhibit better anti-radiation performance. At low-temperature conditions, the initial generation rate and transport time of electron-hole pairs in the oxide layer decrease; oxide-trap charges and interface states are reduced due to the decrease in recombination current, so Gummel characteristics are significantly improved. After total dose irradiation of 1 Mrad (Si), f_T and f_max increased by 10% and 8%, respectively. The RF characteristics are improved by the TID. This work provides a reference for the development and application of SiGe-on-SOI HBT aerospace devices.