The invention discloses a cable fault detection and analysis method. According to the method, an impedance frequency spectrum and a phase frequency spectrum of a cable are taken as basis, subsection characteristic impedance on an impedance frequency spectrum attenuation trend curve is calculated with a subsection interception method, an equation of equivalent impedance is established, R, L, G and C parameters of cable transmission impedance are calculated, a transmission impedance model based on R, L, G and C parameters is obtained, an error distance graph with a cable distance length serving as a variable is obtained through error calculation and comparison of the transmission impedance model and the tested impedance frequency spectrum and phase frequency spectrum, finally, local zero points on the error distance graph are analyzed, and fault detection and fault type identification are realized. Compared with the prior art, on the basis of a relative signal transmission rate calculation method with low calculation difficulty and high calculation accuracy, accurate fault positioning and multi-point fault positioning can be realized, and the fault type identification can be realized.