Embodiments of the invention provide a brake pad and a thickness detection method, and belong to the field of an automobile brake system. The brake pad comprises a backboard, a thermal insulation layer, a friction block, and lead-out wires, the backboard is connected with the thermal insulation layer through the friction block, the friction block is provided with a groove, metallization processing is performed on a first sidewall of the groove to form a first electrode layer, metallization processing is performed on a second sidewall of the groove to form a second electrode layer, the lead-out wires comprise a first leading wire and a second leading wire, the first leading wire is electrically connected with the first electrode layer, and the second leading wire is electrically connected with the second electrode layer. According to the brake pad, the capacitance between the first electrode layer and the second electrode layer is acquired in real time, the thickness change of the brake pad is obtained through the change of the capacitance, the abrasion state of the brake pad is obtained in real time through the thickness change of the brake pad, drivers can maintain and replace the brake pad in advance, and hidden risks during driving can be reduced.