Single-event-transient response of 22-nm technology ultra-thin-body fully-depleted silicon-on-insulator transistor is examined by technology computer-aided design numerical simulation. The influences of ground plane doping, heavy ion injection location, gate work function and substrate bias on single-event-transient characteristic are systematically studied and analyzed. Simulation results show that the influences of ground plane doping and quantum effects on single-event-transient (SET) are relatively small. The SET characteristics and collected charge are strike-location sensitive. The most SET-sensitive region in ultra-thin-body fully-depleted silicon-on-insulator transistor is located near the drain region. When gate work function varies from 4.3 eV to 4.65 eV, the transient current peak is reduced from 564 μA to 509 μA and the collected charge decreases from 4.57 fC to 3.97 fC. The transient current peak is strongly affected by substrate bias. In contrast, the total collected charge depends only weakly on substrate bias.