The invention discloses a downhole tool realizing the stable impact effect through pressure pulses. The downhole tool is suitable for the field of petroleum drilling. According to the technical scheme, an upper connector, an upper shell, a lower shell and an anvil block are sequentially connected through screw threads; an annular check ring is located between the upper connector and an inner cylinder and is axially located through the inner cylinder; the lower end of a belleville spring is adjacent to a hammer base and is axially located; a piston and the lower end of a splitting sleeve are connected through threads; the upper end of a folded spring is connected to a connection sleeve, and the lower end of the folded spring is adjacent to a locating sleeve and is axially located; a half-dividing ring is located in a groove of the anvil block, and an octagonal sleeve is fixed to the lower shell through threads and is clamped between the lower shell and the anvil block. According to the downhole tool, frictional resistance between lower drills of existing horizontal wells and extended reach wells and well walls can be effectively lowered, the backing pressure problem in the well drilling process can be solved, the well drilling efficiency can be improved, and downhole accidents such as jamming can be avoided.