Aging in XLPE will likely lead to space charge accumulation in it. In this paper, based on polarization and depolarization currents (PDC), a trapped charge measurement method is proposed, which can measure the accumulated space charge in XLPE. First, the de-trap current of trapped charge was extracted by subtracting the stable values of depolarization current and conduction current from the polarization current. Then, the $i_{\text{dt}}\cdot t\sim\ln(\mathrm{t})$ curve can be obtained from calculated parameters, which characterizes the density and depth of trapped charge. Finally, the method proposed in this paper were validated by changing different experimental conditions.