Lifting device for protecting integrity of precast pile body and lifting method thereof

The invention discloses a lifting device for protecting the integrity of a precast pile body and a lifting method thereof.The lifting device comprises a column sleeve, sliding grooves are formed in the inner wall of the column sleeve, the multiple sliding grooves are formed in the circumferential direction of the column sleeve at intervals, and the lower ends of the sliding grooves penetrate through the lower end face of the column sleeve; the lower end of the retaining piece is installed in the sliding groove in a turnover mode, the column sleeve is provided with a hole channel communicated with the sliding groove, and the hole channel is aligned to the upper end; the anti-falling part is telescopically mounted in the through hole; the lifting hook comprises a supporting part, a bearing part and a cable connecting part, the bearing part is connected between the lower end of the supporting part and the lower end of the cable connecting part, a hook opening is formed between the upper end of the supporting par