Shallow gas is composed of all kinds of shallow buried natural gas resources ( ＜1500 m) with rela- tively small reserve for each gas resource． It has some advantages such as shallow burial depth，good physical properties and the huge accumulations． Based on the Wigner- Vill distribution，a general spectral decomposition method is applied in the shallow gas detection． Cone- shaped kernel function filtering method is used to suppress cross- terms of the Wigner- Ville distribution，which is tested on field seismic data． Because of shallow gas reser- voir has a characteristic that low frequency energy is stronger and high frequency energy is weaker，it indicates the presence of shallow gas successfully．