Two retired high-voltage cross-linked cables with service years of 16 and 32 are chosen to conduct a 180-day prequalification test to research the diversity of space charge behavior and evaluate the reliability of reusing these cables for practical operation. Space charge behavior in cross-linked polyethylene(XLPE)insulation of the samples before and after aging test is tested by the pulse electro acoustic(PEA) method, and space charge characteristics of the samples is investigated. Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction(XRD) experiments are used to observe changes on micro-structure and aggregation structure of each sample. Experiments reveal the potential relationship between the structural changes and space charge behavior, including the characteristic of migration, accumulation and dissipation of space charge. The results show that the impurities causing severe accumulation of space charge inside the samples of the cable with 16 service years. After the accelerated aging test, reduction of impurities and annealing effect decreases the accumulation of space charge and speeds up dissipation process. On the contrary, the accumulation and dissipation of space charge inside the cable with 32 service years is moderate. After the accelerated aging test, the oxidative degradation and destruction of crystalline structure result in aggravation of space charge accumulation and more moderate dissipation process of space charge.