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为了研究加速热氧老化对中交联聚乙烯(cross-linked polyethylene，XLPE)电缆绝缘聚集态结构和介电强度的关联性，对XLPE电缆绝缘进行了X射线衍射实验、扫描电子显微镜观察、差示扫描量热分析、工频击穿实验和氧化诱导期测量。实验结果表明：氧化诱导期先快速下降然后接近于0。根据氧化诱导期实验可以将加速热氧老化可以分为两个阶段，即重结晶期和热氧老化期。在重结晶期结晶度、晶体熔融温度和工频击穿场强略微上升。与此同时，氧化诱导期快速下降，表明试样内部的抗氧化剂被大量消耗。在热氧老化期结晶度、晶体熔融温度和工频击穿场强均显著下降，氧化诱导期接近于0，表明试样内部的抗氧化剂已基本消耗完毕。此阶段XLPE中氧化反应可以自发加速进行，产生了较多的断链及氧化产物。根据上述实验结果，提出了一种基于热膨胀力和氧化反应的热氧老化模型，对老化过程中XLPE电缆绝缘聚集态结构和介电强度的劣化过程进行了解释。“,”In order to study the influence of accelerated thermal-oxidative aging on aggregation structure and dielectric strength of XLPE insulation, The X ray diffraction (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC) tests, ac breakdown experiments and oxidation induction time (OIT) experiments were done. Depending on the results that OIT decreases dramatically and then is close to 0, the aging process can be divided into two stages. In the recrystallized stage, the crystallinity, melting temperature and breakdown field strength increase slightly. Meanwhile, the OIT decreases significantly, which reflects the antioxidant is consuming. In the thermal-oxidative aging stage, however, the crystallinity, melting temperature and breakdown field strength decrease dramatically. The OIT is close to 0, indicating the antioxidant is exhausted. During this process, macromolecules break into small molecules, which create chain scissions and oxidation products. The thermal-oxidative aging model depending on thermal expansion and oxidation reaction is presented to explain degradation of aggregation structure and dielectric strength of XLPE insulation in accelerated thermal-oxidative aging.