In this paper, we implement a Time-Frequency Domain Re ectometry(TFDR) system through the instruments of PCI extensions for Instrumentation(PXI). Moreover, the improved TDR methodology is suggested to reduce the blind spot which is caused by comparatively low performance of PXI instruments. The TFDR system is composed of following three PXL instruments: the Arbitrary Waveform Generator(AWG) module for generating the input signal, the Digital Storage Oscilloscope(DSO) module for acquiring the input and re ected signals, and PXI controller module for performing the control of total PXI modules and the execution of main algorithm. This TFDR algorithm can measure the more accurate fault location than the traditional methodologies by adopting the time-frequency analysis techniques. For the problem of the blind spot, the classical correlation function is used between the input and re ected pulse signals. The usefulness of the proposed system and methodology is veri ed by real experiments.