The invention discloses a method for positioning an incomplete disconnection fault of a flexible cable, which comprises the following steps: short-circuiting one end of a faulty cable; connecting the other end of the faulty cable to a pointer multimeter; placing a mobile roller wheel under the faulty cable to drag the faulty cable, wherein due to the squeeze of the incomplete disconnection point of the faulty cable by the mobile roller wheel, the cable generates changes in tensile and compression forces on the mobile roller wheel so as to cause obvious changes in the resistance of the incomplete disconnection point of the cable; and observing the change of the pointer of a pointer multimeter serially connected in a cable circuit to determine the incomplete disconnection point of the cable. The positioning method can conveniently, quickly and accurately position the incomplete disconnection point of the cable, avoid causing unnecessary cable replacement and eliminate safety hazards.