A biopsy needle, comprising: an inner needle assembly, comprising a first plug-in connection portion plugged in with a fastener, wherein the first plug-in connection portion comprises two first outer limiting walls arranged in parallel and a first limiting plate located between the two first outer limiting walls, and the first limiting plate is provided with a first protrusion; an outer needle assembly, comprising a second plug-in connection portion plugged in with the fastener, wherein the second plug-in connection portion comprises two second outer limiting walls arranged in parallel and a second limiting plate located between the two second outer limiting walls, and the second limiting plate is provided with a second protrusion; and the fastener, comprising a third plug-in connection portion plugged in with the first plug-in connection portion, and a fourth plug-in connection portion plugged in with the second plug-in connection portion, wherein the third plug-in connection portion comprises two first inner limiting walls that have a T-shaped longitudinal section and that match the first outer limiting walls, and a third limiting plate arranged between the two first inner limiting walls and matching the first limiting plate, wherein the third limiting plate is provided with a first groove mating with the first protrusion; and the fourth plug-in connection portion comprises two second inner limiting walls that have a T-shaped longitudinal section and that match the second outer limiting walls, and a fourth limiting plate arranged between the second inner limiting walls and matching the second limiting plate, wherein the fourth limiting plate is provided with a second groove mating with the second protrusion, wherein the first outer limiting walls are arranged perpendicular to the first limiting plate, and a first gap is provided between each of the first outer limiting walls and the first limiting plate. an inner needle assembly, comprising a first plug-in connection portion plugged in with a fastener, wherein the first plug-in connection portion comprises two first outer limiting walls arranged in parallel and a first limiting plate located between the two first outer limiting walls, and the first limiting plate is provided with a first protrusion; an outer needle assembly, comprising a second plug-in connection portion plugged in with the fastener, wherein the second plug-in connection portion comprises two second outer limiting walls arranged in parallel and a second limiting plate located between the two second outer limiting walls, and the second limiting plate is provided with a second protrusion; and the fastener, comprising a third plug-in connection portion plugged in with the first plug-in connection portion, and a fourth plug-in connection portion plugged in with the second plug-in connection portion, wherein the third plug-in connection portion comprises two first inner limiting walls that have a T-shaped longitudinal section and that match the first outer limiting walls, and a third limiting plate arranged between the two first inner limiting walls and matching the first limiting plate, wherein the third limiting plate is provided with a first groove mating with the first protrusion; and the fourth plug-in connection portion comprises two second inner limiting walls that have a T-shaped longitudinal section and that match the second outer limiting walls, and a fourth limiting plate arranged between the second inner limiting walls and matching the second limiting plate, wherein the fourth limiting plate is provided with a second groove mating with the second protrusion, wherein the first outer limiting walls are arranged perpendicular to the first limiting plate, and a first gap is provided between each of the first outer limiting walls and the first limiting plate.