Abstract: It is difficult to measure the time difference for the wideband frequency hopping(FH) signal with low signal-to-noise ratio(SNR) by envelope detection method. A time difference measurement method is proposed for wideband frequency hopping(FH) signal with low SNR based on cross correlation and interpolation calculation. The computational load is reduced through time-frequency domain transformation. Signal correlation peaks are obtained via correlation processing, followed by interpolation of these peaks to further enhance the time difference measurement accuracy. The simulation results indicate that this method can effectively improve the time difference measurement accuracy for wideband FH signals, thereby enhancing the system's time difference localization precision.