In this paper, we studied the mechanical and thermal properties on slice XLPE sheet from 22 kV and 154 kV power cables. Interface structures are XLPE/semiconductor and XLPE/water/semiconductor. We evaluated mechanical property, thermal analysis, moisture analysis. Based on mechanical and thermal properties of the 22 kV XLPE sheet, elongation, mechanical strength, and melting point were evaluated to be 485.48 %, 1.74 kgf/$ extrm{mm}^2$ and $102.48^{circ}C$, respectively. It was also evaluated from the mechanical and thermal properties of 154 kV XLPE sheet that elongation, mechanical strength, and melting point are 507.81 %, 1.8 kgf/$ extrm{mm}^2$, $106.9^{circ}C$, respectively. A region shows a rapid increase in tension strength, and B region only shows increase in elongation under 1.0 kgf/$ extrm{mm}^2$, C region shows increase in both elongation and tension strength. Difference of melting point came from the chain of XLPE polymer and the difference of crystallization. Moisture density of semiconductor showed 800 ∼ 1200 ppm before extrude, 14000 ∼24000 ppm after extrude. These values were higher than the moisture density of XLPE (300∼560) ppm.