Display panels need to be tested after being produced, i.e., conducting a test circuit board (a flexible printed circuit (FPC) in the display apparatus that is matched to the display panel) with a to-be-tested display panel to determine whether the display panel is non-defective according to a display situation thereof. Usually, the to-be-tested display panel is secured on a securing platform of a test machine during the detection. The test circuit board is secured on a pressure head of the test machine that is pressed downward while an operator calibrates a position of the test circuit board with the naked eye, so that a plurality of first connecting fingers 11 on the test circuit board 10 contact a plurality of second connecting fingers 21 on the to-be-tested display panel 20 one by one, as shown in FIG. 1, thereby conducting the test circuit board 10 with the display panel 20. However, the method of calibrating through the naked eye of an operator s low in efficiency and accuracy, and tends to cause a short circuit between the test circuit board and the display panel.