Optoelectronic metal oxide semiconductor (MOS) solid-state relays integrate optoelectronic isolation technology with MOS field-effect transistor (MOSFET) processes, achieving reduced device dimensions and expanding application domains. Currently, there is limited research on this type of device both domestically and internationally. Particularly when exposed to complex radiation environments, the reliability of the device requires evaluation. This paper investigates the total dose resistance characteristics of the input-side light emitting diode (LED) and output-side MOS device in a specific opto-MOS solid-state relay model through gamma-ray total dose irradiation experiments. Experimental results indicate: Within the 0–100 krad (Si) dose range, the device’s LED terminal exhibits excellent radiation resistance in forward characteristics, while reverse characteristics demonstrate sensitivity to ionizing radiation. Within the 0–300 krad (Si) dose range, the device’s turn-on voltage remains stable. However, the turn-on resistance of the MOS terminal and the turn-off leakage current are significantly affected by radiation, showing a marked upward trend with increasing cumulative dose.