Abstract: This article focuses on the co seismic waveforms collected by the VP type broadband inclinometer at the Chengde Seismic Station and the BBVS-120 type broadband seismometer at the same site.Using the methods of wavelet analysis and short time Fourier transform, the six seismic waveforms were analyzed, including time frequency analysis and frequency response, energy concentration at 0-0.5HZ.They have high consistency in waveform, frequency response, and power spectral density.Using empirical formulas to fit the relationship between the maximum amplitude and magnitude, the maximum amplitude formulas for the near and far earthquakes of the broadband tiltmeter is obtained.here is a good correspondence between the maximum amplitude of the broadband inclinometer and the broadband seismometer in the Chengde area.Using the seismic wave body wave magnitude calculation formula, three seismic waves were selected to calculate the body wave magnitude for the earthquakes recorded by the broadband inclinometer and broadband seismometer. The results showed that when the seismic wave frequency was less than 0.5HZ, the corresponding relationship between the body wave magnitudes calculated by the two was good.