The rapid development of power system puts forward higher requirements for the incipient fault location of cable. Aiming at the problem that the traditional traveling wave method is susceptible to environmental interference and seriously affects the positioning accuracy, considering the low energy of noise signal, this paper proposes a method based on two-terminal signal time-frequency transformation to reduce the influence of noise on positioning accuracy. Firstly, based on the transmission line theory, the principle of fault location is analyzed. Then, in order to improve the anti-interference ability of the method, the time-frequency domain transformation of the collected double-ended current signal is carried out, and the transmission delay of the two signals is calculated by the time-frequency cross-correlation function to realize the initial fault location. Finally, the simulation results show that the positioning accuracy of the initial fault location before and after noise interference is 0.44% and 1.24% respectively, which shows that the proposed method has high positioning accuracy and anti-interference ability.