Abstract: In order to develop 220kV and above grade crosslinked polyethylene (XLPE) cable insulation materials, it is necessary to make complete evaluation of the main properties of the base resin and manufactured materials. This work describes the design of components and manufacture process of domestic 220kV cable insulation material. Compared with imported insulating materials of the same grade, purified resin for testing is obtained by extracting crosslinking agent, the macromolecular structure and rheological properties of domestic and imported base resin are compared and tested. The AC electrical properties, thermal oxygen aging performance and crosslinking performance of XLPE are compared and analyzed. The results show that the molecular weight and its distribution, branching degree, chemical composition and rheological properties of domestic base resin are similar to those of imported materials. The domestic 220kV XLPE insulation material has similar breakdown strength as imported materials, which is improved compared with the original base resin. Besides, the dielectric loss performance of domestic 220kV XLPE insulation material is better than that of imported materials. The oxygen aging performance, the crosslinking degree and crosslinking reaction efficiency are superior to those of imported materials, and the scorch resistance is comparable to that of imported materials. The relatively better oxidation resistance of domestic XLPE leads to inevitable increase of crosslinking agent and relatively large amount of crosslinking byproduct; however the time required for saturation degassing is basically the same.