The invention relates to the technical field of a hydraulic bolt structure, particularly to an insulating hydraulic bolt and a processing technology thereof. The insulating hydraulic bolt can effectively block DC current and perform an insulating function. The insulating hydraulic bolt comprises a bolt body, a tapered sleeve and two nuts, wherein the outer surface of the tapered sleeve and the flat surfaces of the nuts are coated with Al2O3 ceramic layers. The processing technology of the insulating hydraulic bolt is characterized in that the Al2O3 ceramic layers are thermally sprayed on the outer surface of the tapered sleeve and the flat surfaces of the nuts. The processing technology comprises the following steps: 1, carrying out machining on a forged piece; 2, sequentially carrying out washing and drying on the tapered sleeve and the two nuts; 3, carrying out sand blasting operation on the washed tapered sleeve and nuts within 4 hours; 4, using a coating machine to melt aluminum oxide powder and spray the aluminum oxide powder on the outer surface of the tapered sleeve and the flat surfaces of the nuts; and 5, grinding the thermally coated surfaces until a coarse requirement is met.