The invention provides an apparatus and method for testing the shear tolerance strength of a head of a disk-shaped suspension type insulator. The apparatus comprises a jig, a pendulum bob, a position detecting mechanism, a height adjusting mechanism and a supporting mechanism, wherein the jig is used for being in clamping connection with the insulator to be tested; the height adjusting mechanism is arranged above the jig and is connected with the supporting mechanism in the height direction in a position-adjustable manner; a pendulum rod end in the pendulum bob is connected with the height adjusting mechanism, and a heavy bob in the pendulum bob is used for applying impact force to the insulator to be tested; the position detecting mechanism is connected with the height adjusting mechanism to detect the position of the pendulum bob. The apparatus disclosed by the invention can test the shear tolerance strength of various disk-shaped suspension type insulators with high data accuracy, and helps designers to deepen accurate understanding of the shear tolerance strength of heads of various disk-shaped suspension type insulators to further optimize the design by combing the shear strength during designing, and besides, the safety performance of the disk-shaped suspension type insulator is improved.