An exemplary device (27) for adjusting angle of a base plate (2710) includes: two side walls (21) being parallel to and spaced apart from each other, each of the side walls including a pivot hole (217); a base plate disposed between the two side walls and pivotally attached to the side walls via the pivot axles; and a plurality of magnetism members (211, 212 and 2715) disposed on the base plate (2710) and the side wall. The magnetism members configures for holding the base plate stably in a starting position and further configures to allow the base plate to be displaced from the starting position by manual pressure applied to the base plate, such that a tilt angle of the base plate relative to the two side walls is adjustable up or down as desired. An exemplary apparatus (2) for testing display modules using the angle adjusting device is also provided.