Adjustable positioning device of LED backlight unit

The invention discloses an adjustable positioning device of a light emitting diode (LED) backlight unit, which solves the problem that a positioning die for bearing the backlight unit in the conventional equipment cannot be adjusted according to the size of a backlight element. The device comprises four positioning blocks arranged on chutes (13) symmetrically formed on diagonals of an oblong die bottom plate (1) respectively, and four cushion blocks symmetrically arranged on left and right, upper and lower symmetric axes of the oblong die bottom plate (1); the positioning blocks and the cushion blocks are connected with the die bottom plate (1) together through movable and fixed bolts respectively; the large-size product positioning area of the upper right corner of the positioning block is provided with a large-size product supporting face (22) and a large-size product right-angled positioning vertical face (21); and the small-size product positioning area of the lower left corner ofthe oblong positioning bl