A precision metal sheet bend angle adjustment device is provided, which includes a lifter plate, a wedge plate, a support plate and a positioning frame. The lifter plate has a tapered bottom face. The wedge plate has a tapered top face and side recesses. The support plate has a top guiding grove and the positioning frame includes a rotary dial and adjustment screw. The support plate is fixed on the positioning frame. The wedge plate is located on top of the assembly such that it is able to slide within the guiding grove of the support plate. The adjustment screw of the rotary dial is inserted into the side recess of the wedge plate. The lifter plate rests on top of the wedge plate within the positioning frame such that, as the wedge plate slides back and forth, the lifter plate moves up and down within the positioning frame by rotating the rotary dial clockwise or counter clockwise. The die of the metal sheet bending equipment can be moved vertically while sitting atop the lifter plate.