Abstract: The self-healing property of metallized film capacitors is the key factor affecting reliability and lifetime. To study the effect of internal self-healing on capacitor's lifetime, based on the actual operating conditions of DC-link capacitors in the flexible HVDC transmission system, the accelerated aging tests of metallized film capacitor elements under different voltages were carried out in this paper. A large number of morphological parameters of self-healing points were extracted by image recognition technology, and statistical models of characteristic self-healing parameters under HVDC were established. The influence of self-healing characteristics on lifetime of DC metallized film capacitor is revealed, and a capacitor lifetime prediction method based on characteristic quantity of capacitance loss during self-healing process is proposed. This study provides an efficient method for reliability evaluation of DC-link capacitors.