The invention discloses a novel three-phase integrated high-voltage insulation sleeve which consists of three insulation sleeves; the lower ends of the three insulation sleeves are connected with one end of a connecting pipe through a butt flange; the other end of the connecting pipe is respectively connected with fixed cavities; the three insulation sleeves are arranged in an epsilon shape; pressing leads are arranged in the insulation sleeves; seamless corrugated pipes and grading shields are arranged on the pressing leads. The connecting pipe takes the shape of a fold line; the three insulation sleeves are arranged in an inclined manner, with a same inclination angle; the insulation sleeves on two sides are higher than the insulation sleeve in the middle. During the process of performing the entire AC voltage withstand test on a three-phase cable, once inflation operation is only needed to be carried out on SF6 gas in a cable bin, the time consumed by the entire AC voltage withstand test can be shortened greatly.