To investigate the thermal distribution characteristics in insulator strings incorporating zero-value insulators, this study selects seven XP-70 type suspended disc insulator strings as the focal subjects. A sophisticated finite element simulation was employed to develop a coupled electric-thermal multiphysics model, aimed at examining how zero-value insulators influence the electrical potential and thermal distribution across various segments of the insulator strings. The findings reveal that standard insulator strings exhibit a relatively narrow temperature fluctuation range, whereas those with zero-value insulators demonstrate a significantly wider range. The study also observed that the placement of zero-value insulators variably impacts the thermal distribution along the strings, yet consistently proves effective in their identification. Importantly, this research substantiates the feasibility of employing infrared thermal imaging for detecting zero-value insulators, offering vital theoretical backing for such detection methods and enhancing the reliability of infrared-based diagnostics in this context.