A silicon–alumina oxide–silicon oxide–silicon nitride–silicon oxide–silicon device with a bilayer Al2O3/SiO2 blocking oxide (SAONOS device) is a candidate ultraviolet (UV) nonvolatile total dose (TD) radiation sensor. In this work, UV radiation induces a significant increase in the threshold voltage VT for an SAONOS device under positive gate voltage (PGV). The change in VT for the SAONOS device after UV radiation has a correlation with UV-TD up to 100 mW‧s/cm2. The experimental results indicate that the radiation-induced increase in VT for the SAONOS device under PGV is nearly 3 V after 100 mW‧s/cm2 TD-UV radiation. The performance of the SAONOS device as a UV nonvolatile TD sensor was thus improved. Meanwhile, the experimental results show that the VT retention performance of the SAONOS device after UV irradiation is also improved after 10 years of retention. The SAONOS device in this study has demonstrated its feasibility for UV nonvolatile TD radiation sensing application in the future.