The invention relates to an anti-theft nut of a high-pressure anti-theft nut, in particular to a detachable anti-loosening anti-theft nut. The detachable anti-loosening anti-theft nut comprises a nut body. The detachable anti-loosening anti-theft nut is characterized in that the nut body is equipped with a fixed nut and a fastening sleeve; the fixed nut is mounted in the fastening sleeve; the fixed nut is a circular structure, a fastening slot is formed in the lower part of the fixed nut; a pressing deformation anti-loosening part is arranged on the inner side wall of the fastening slot; the outer ring of the fastening sleeve is a prismatic structure; and the inner part of the fastening sleeve is bugled with a fastening block matched with the fastening slot. The detachable anti-loosening anti-theft nut has the advantages of being simple in structure, detachable, low in cost and good in anti-loosening anti-theft effect.