With the development of semiconductor technology, the small size silicon-on-insulator metal-oxide-semiconductor field-effect transistor devices start to be applied to the aerospace field, which makes the device in use face dual challenges of the deep space radiation environment and conventional reliability. The small size device reliability test under ionizing radiation environment is conducible to the assessing of the comprehensive reliability of the device. With reference to the national standard GB2689.1-81 constant stress life test and accelerated life test method for the general electric stress, the conventional reliability of the sub-micron type partially-depleted silicon-on-insulator n-channel metal-oxide-semiconductor is studied under the ionizing radiation environment. The experiment is divided into three groups marked by A, B and C. For all the experimental devices, the gate oxide tox=12.5 nm, channel length L=0.8 μm and width W=8 μm, and nominal operating voltage V=3.5 V. We carry out the electrical stress test on A group after irradiation with γ -ray dose up to 1×104 Gy (Si) under the bias condition. Before group B is tested, it has been irradiated by the same dose γ -ray and annealed for one week. Group C is not irradiated by γ -ray before the electric stress test. After irradiation we measure the DC characteristics of the devices: the drain current versus gate voltage (IDS-VGS) and the drain current versus drain voltage (IDS-VDS). The hot carrier injection (HCI) experiment is periodically interrupted to measure the DC characteristics of the device. The sensitive parameters of HCI and irradiation are VT, GM and IDlin, and after HCI stress, all parameters are degenerated. Through the contrast test, we qualitatively analyze the influences of the oxide trap charge and interface state on the sensitive parameters. We obtain the curve of the oxide trap charge and interface state versus time, and the influences of the different stages on device parameters. The results show that the combination of the total dose radiation environment and electrical stress causes the sensitive parameters of the device to rapidly degrade, this combination of these two factors gives rise to bigger effect than a single influence factor.