An improved safe and convenient disposable automatic lancet, comprising a housing (1), a needle core (2), a spring (3) and a protective rod (4), wherein, a pressing arm of a trigger button (10) is divided into a first pressing leg (11) and a second pressing leg (19), and the first pressing leg (11) is used for triggering an elastic arm in a locking structure to form a press-type trigger structure, and the second pressing leg (19) fits with a safety sleeve (20) and a press-down channel (17) to achieve a safety function of the trigger button (10)； a barb (12) on the second pressing leg (19) fits with a self-locking hook (13) on the housing (1) so as to achieve a self-locking function after one press. In order to shorten the exposed needle length of a needle body on the needle core (2), in the automatic lancet, the distance between the second pressing leg (19) and the needle tip (7) is designed to be less than the distance between the first pressing leg (11) and the needle tip (7). Since the exposed needle length depends on the position of the safety sleeve (20), the exposed needle length is shortened, therefore the puncture performance increases, which enables the design of the lancet to be more reasonable and practical.
