The present invention discloses an anti-theft lockset, belonging to the field of hardware, mainly characterized in that the key comprises a key handle (1), a connecting portion (2) and a key head (4), the key head (4) being mounted on the connecting portion (2), the connecting portion (2) being connected to the key handle (1); columns are provided around a hole, into which the key head (4) is to be mounted, on the connecting portion (2); a long hole (28) is formed on the key head (4); sliders (7) corresponding to the columns (3) are provided in the lock cylinder (12), and a conical chute (8) or bulge (30) fitted with the pin tumbler (23) in the fourth pin tumbler hole (10) is provided on the slider (7); the pin tumbler (22) in the third pin tumbler hole (11) is matched with biting (5) on the key head (4); a slide bar (14) is provided in the lock cylinder (12), with a plurality of flanges (15) different in the outer diameter being provided on the slide bar (14); the pin tumbler (24) in the sixth pin tumbler hole (13) is resisted against the outer circumferential walls of the flanges (15); the slide bar (14) can extend into the long hole (28) of the key head (4); and springs (9, 17) are provided at ends of both the slider (7) and the slide bar (14). The present invention has such a scientific and reasonable structure, achieves multiple and effective guarding against theft and even eliminates the possibility of technical unlocking.