The test results for emulative signal indicate that the time delay estimation method Of bispectrum has the capacity to suppress Gauss noise and can accurately estimate the time delay of signals. Compared with Fourier transform method, the spectrum power reconstruction method of bispectrum has higher accuracy and capability. The research results show that the characteristic parameter distribution of bispectrum has a good consistent characteristics to the normal earthquake precursory monitoring data, but has a obvious dispersion characteristics to the abnormal data, which indicats that bispectrum has the discrimination capability to earthquake precursory anomalies in monitoring data.