The stable operation of high-voltage bushings is a crucial guarantee for maintaining the secure and reliable power supply of the electrical grid. During the operation and maintenance of bushings in cold regions during the winter season, the environmental temperature will significantly impact the testing and evaluation results. Existing evaluation data mostly pertain to temperatures ranging from room temperature to operational temperatures. Hence, the test data within this range is not applicable for assessing the primary insulation status of bushings in low-temperature conditions. Based on this, the paper prepared a scaled-down model of the bushing capacitor core and conducted wide-frequency dielectric response tests on the scaled-down model within a temperature range of −25 ℃ to 75 ℃ in a laboratory environment. The study revealed the influence patterns of testing temperature and insulation aging on the changes in the primary insulation dielectric characteristics of the bushing. It also elucidated the non-linear variation patterns of the dielectric loss factor curve at low frequencies in response to the excitation amplitude. The research findings in this paper provide a crucial theoretical foundation for the modification of insulation status assessment methods and the formulation of maintenance strategies for bushings in cold regions.