It is the first time for large volume air-gun excited in the Yangtse River，so it is necessary to study the time-frequency characteristic based on the linear stacked seismic data from records from temporary stations near the fixed fields and seismic stations. Air-gun signal propagation distances were detected using the stacked seismic data to analyze the environmental impact on signal propagation distance. The results showed that：(1)the air-gun signal produced by bubble pulses，pressure pulses and surface wave can be received by the temporary station near by fixed field；(2)the dominant frequency of bubble at 5Hz or so can be received by both near-field stations and far-field stations，pressure pulses rapidly weakens and the dominant frequency bands get narrower as epicentral distance increases；(3)the longest spread distance of signal is 260km，the nearest is 180km，and the signal can travel further in evening.