At various low-temperature conditions, it is difficult to obtain an accurate sensing response due to temperature-dependent material properties such as bandgap and resistivity of semiconductors. In this study, a gallium nitride (GaN)-based ultraviolet (UV) photodetector with a microheater was demonstrated to compensate the low-temperature effects. A parallel-type platinum microheater array was fabricated to supply thermal energy by Joule heating. In addition, a silicon oxide layer was deposited between the heater and the GaN surface, allowing an independent voltage supply. Therefore, the change in the signal level was successfully recovered to the initial state in the temperature range of -27.4-11.5 °C within ~0.64% error without electrical interference. This study supports an active, accurate, and reliable method for the stable measurement of UV signals in various low-temperature environments such as freezer warehouses, Antarctic research stations, and in space.