Abstract: To distinguish strata with thickness of about 1m under depth of 1500m, a seismic instrument must have the ability to record signals whose frequencies are more than 1000Hz And its instantaneous dynamic range should reach up to about 120dB Either the early centralized digital seismograph or the modern 24bit telemetric seismograph cannot meet this demand Based on even medium and using Ricker wavelet with dominant frequency of 150Hz, this paper calculated theoretically the attenuated energy and absorbed frequency during propagation of seismic waves The instantaneous dynamic range and the highest frequency that can be recorded were then analyzed It is shown that for seismic reflections with traveltime exceeding 15s, their instantaneous dynamic ranges will be about 60dB, and the highest frequency of signals cannot exceed 170Hz