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为研究实际电缆运行中的温度梯度效应对高压直流交联聚乙烯(cross-linked polyethylene，XLPE)电缆绝缘长期运行可靠性的影响，采用自制的多组片状试样适用的温度梯度场–直流电场协同老化装置，分别对3种XLPE绝缘料(包括国产XLPE料、纳米改性后的XLPE料、北欧化工产高压直流XLPE料)进行温度梯度场–直流电场协同老化试验。为了进行对比研究，同时对以上3种XLPE绝缘料进行了传统高温场–直流电场协同老化试验。通过电声脉冲法空间电荷测量设备，测量了不同老化时间后(未老化、老化一个月和三个月)三种 XLPE 试样的空间电荷特性。同时测量了3种XLPE 试样老化后的电阻率变化及红外光谱特性。结果表明，高温老化试样中空间电荷在体内均匀分布；而温度梯度老化试样中异极性空间电荷主要聚集在两电极附近。同时3种XLPE电阻率均随老化时间增加而降低，且温度梯度老化试样电阻率低于相同条件下的高温老化试样。另外，国产纳米改性XLPE老化后羰基吸收峰峰值最小，表明其老化程度最低，体内电荷积聚最少。“,”In order to study the influence of temperature gradient on long-term reliability of high voltage direct current (HVDC) cross-linked polyethylene (XLPE) cable insulation during actual operation, homemade temperature gradient-DC field cooperative aging device for multi-group sheet specimen were used to carry out temperature gradient-DC stress cooperative aging on three kinds of XLPE insulating materials (including domestic XLPE, nano-modified XLPE and HVDC XLPE produced by Borealis). Furthermore, traditional thermo-electrical aging were performed on above three kinds of XLPE as parallel group. Space charge characteristics of the three kinds of XLPE after aging for different times (one month and three months, respectively) were measured by pulsed electro-acoustic (PEA) method. Moreover, resistivity and infrared spectrum of the XLPE before and after aging were measured, respectively. Results show that the space charge distribution evenly in the bulk of thermo-electrically aged specimens, while hetero-charge in the specimens aged under temperature gradient mainly accumulate near electrodes, and resistivity of the XLPE decrease with aging time. Furthermore, the resistivity of thermo-electrical aged samples are lower than those that aged under temperature gradient at the same time. In addition, domestic nano-modified XLPE has the smallest carbonyl absorption peak value, which indicates the lowest aging degree and the least space charge accumulation in the samples.