An under-screen biometric identification apparatus, applicable to an electronic device having a display screen, the under-screen biometric identification apparatus comprising: a lens unit, comprising at least one aspherical lens, structured to be disposed under a display screen for receiving an optical signal generated when light is reflected by a finger above the display screen, wherein the optical signal is used to detect biometric information of the finger; a lens barrel structured for accommodating and fixing the lens unit, wherein a lower surface of the lens barrel extends downward at a barrel opening of the lens barrel to form a first fixing structure, the lower surface of the lens barrel extends downward at an edge of the lens barrel to form a second fixing structure, the lens barrel forms a cavity between the first fixing structure and the second fixing structure, and the lens unit is fixed in the first fixing structure; a sensing chip, comprising an optical sensing array having a plurality of optical sensing unit, structured to be fixed on a flexible printed circuit board and disposed under the lens unit, a lower surface of the second fixing structure is fixedly connected to the upper surface of the flexible printed circuit board in an edge area of the sensing chip, the sensing chip being configured for implementing optical imaging based on the optical signal passing through the lens unit, wherein a distance between a photosurface of the sensing chip and an imaging surface of the lens unit is greater than or equal to a preset value to enable the sensing chip to operate in a defocusing state; and an optical filter located between the lens barrel and the sensing chip, wherein the optical filter is fixed on an upper surface of the sensing chip, and at least covers a lower surface of the first fixing structure by means of direct contact with a bottom of the lens barrel; wherein the defocusing state refers to that the sensing chip is capable of obtaining imaging of the optical signal corresponding to light reflection of the finger on the photosurface thereof, while an optical signal corresponding to an internal structure of the display screen is incapable of being imaged on the photosurface of the sensing chip. a lens unit, comprising at least one aspherical lens, structured to be disposed under a display screen for receiving an optical signal generated when light is reflected by a finger above the display screen, wherein the optical signal is used to detect biometric information of the finger; a lens barrel structured for accommodating and fixing the lens unit, wherein a lower surface of the lens barrel extends downward at a barrel opening of the lens barrel to form a first fixing structure, the lower surface of the lens barrel extends downward at an edge of the lens barrel to form a second fixing structure, the lens barrel forms a cavity between the first fixing structure and the second fixing structure, and the lens unit is fixed in the first fixing structure; a sensing chip, comprising an optical sensing array having a plurality of optical sensing unit, structured to be fixed on a flexible printed circuit board and disposed under the lens unit, a lower surface of the second fixing structure is fixedly connected to the upper surface of the flexible printed circuit board in an edge area of the sensing chip, the sensing chip being configured for implementing optical imaging based on the optical signal passing through the lens unit, wherein a distance between a photosurface of the sensing chip and an imaging surface of the lens unit is greater than or equal to a preset value to enable the sensing chip to operate in a defocusing state; and an optical filter located between the lens barrel and the sensing chip, wherein the optical filter is fixed on an upper surface of the sensing chip, and at least covers a lower surface of the first fixing structure by means of direct contact with a bottom of the lens barrel; wherein the defocusing state refers to that the sensing chip is capable of obtaining imaging of the optical signal corresponding to light reflection of the finger on the photosurface thereof, while an optical signal corresponding to an internal structure of the display screen is incapable of being imaged on the photosurface of the sensing chip.