The invention relates to a clamp and a process for measuring the shear strength of a brazing interface of a melt-brazing sample. The clamp mainly comprises a base with a sliding chute, an optical axis and a driving mechanism, wherein a sliding block is arranged inside the sliding chute; the optical axis is longitudinally installed in the base and penetrates through the sliding block; the driving mechanism is used for driving the sliding block to slide and comprises a long sleeve which is horizontally arranged at the outer side of the base, and is internally provided with a worm rod, the two ends of the worm rod respectively protrude out of the long sleeve, one end of the worm rod is meshed with a feed screw rod which is longitudinally in the base, the worm rod is transmitted to the feed screw rod and then, the feed screw rod drives the sliding block to slide. According to the clamp provided by the invention, through the structure with novel design, different shear samples can be accurately clamped, and the accuracy of the measuring result can be effectively ensured.