The invention discloses a cable thickness/eccentricity measuring method and a measuring device. The cable thickness measuring method comprises the following steps: (1) selecting/manufacturing a to-be-measured cable test piece; (2) fixing the test piece onto a sample table transmission device; (3) rotating a screw rod so as to enable a travelling cutter to be tangent to one edge of the to-be-measured cable test piece and performing zero clearing; (4) translating the travelling cutter to be tangent to the other edge of the to-be-measured cable test piece, stopping rotating the screw rod, sending data to a single-chip microcomputer by an angle sensor which rotates coaxially with the screw rod, processing the data by the single-chip microcomputer so as to obtain thickness data and displaying the thickness data on a digital displayer. According to the eccentricity measuring method, the eccentricity can be obtained by calculation after the thickness of an inner conducting layer, an outer conducting layer and an insulating layer of the cable is measured. The measuring method is simple to operate, the moving distance of the travelling cutter is calculated by virtue of the screw rod and then the thickness size can be calculated; in addition, due to the use of the digital displayer, human eye errors can be overcome, and the number of reading times during testing can be effectively reduced; the testing accuracy and the testing efficiency are improved.