The invention relates to a backlight source used for a liquid crystal television. The backlight source comprises a light guide plate assembly, an LED lamp strip, a PMMA diffuser plate, a DBEF light enhancement sheet, a black-white shading double-faced adhesive tape frame, a U-shaped inner glue frame and an outer iron frame, wherein the inner glue frame is arranged inside the outer iron frame, an LED lamp strip clamping groove is arranged at one end, disposed at the inner glue frame, on the inner wall of the outer iron frame, the light guide plate assembly, the PMMA diffuser plate and DBEF light enhancement sheet are successively arranged in the inner glue frame in an attached mode from bottom to top, the LED lamp strip is placed in the LED lamp strip clamping groove, the black-white shading double-faced adhesive tape frame is adhered to the top portion of the DBEF light enhancement sheet, the LED lamp strip clamping groove is completely shielded, and a liquid crystal display screen is adhered to the upper portion of the black-white shading double-faced adhesive tape frame; and the light guide assembly comprises an optical glass light guide plate and a reflective film layer adhered to the bottom of the light guide plate, the LED lamp strip comprises an aluminum-base copper-clad laminate and a plurality of SMD LED lamp beads, the LED lamp beads are welded to the aluminum-base copper-clad laminate, the LED lamp beads and the aluminum-base copper-clad laminate are attached together by use of heat conduction silica gel, and the LED lamp beads are right opposite to the side incident surface of the optical glass light guide plate.