Abstract: The differences of the seismic characteristics and frequency of the Huailai explosions, the Sanhe quarry explosions and the natural earthquakes with low magnitude are discussed. The results show that the two different area explosions have obviously different seismic characteristics and frequency distribution, Huailai explosion has stronger P wave energy than S wave and fast attenuation; The main frequencies of P wave and S wave in Sanhe quarry explosion are lower than that in Huailai explosion, S wave and surface wave are confused, and the low frequency developed obviously at different distances; While for natural earthquakes, the effective frequency band is wider and the frequency components are more complex than explosions. Pg/Sg spectral ratios in small-magnitude earthquakes and explosions were studied and cross-band spectral ratios were explored. Results obtained show that the high frequency （＞5 Hz）Pg/Sg spectral ratio discriminants can completely distinguish explosions from low magnitude earthquakes; The spectral ratios of the cross-band related to low frequency （0−2 Hz） of Sg can effectively identify explosions in these two areas, Pg/Sg discriminants of the crossed frequency band can better reflect the difference characteristics of different types of events than that of the traditional single frequency band.