Abstract: The seismic resolution has long been limited to the quarter wavelength. To compress the seismic wavelet, the key problems are signal-to-noise ratio (SNR) and resolution in early stages, and high resolution and high fidelity in late stages. Meanwhile, by using well data, many inversion methods of spanning quarter wavelength have been developed. The success of these methods depends on the preservation of seismic wave amplitude, the accuracy of seismic interpretation, and the compatibility between well data and seismic data. Afterward, researchers achieved seismic inversion without well data constraint, and the corresponding resolution reached the level of reflectivity. Meanwhile, the key problem turned into the credibility of impedance information. In this study, we sort out relevant seismic data and refer to the thoughts and methods of seismic sedimentology, and propose a thin fluvial channel sand body depiction method without well data constraint. This method not only exceeds the limit of quarter wavelength but also guarantees the accuracy of seismic interpretation. Case study is carried out and quarter-wavelength-based superimposed channels are separated. This method shows great prospects for old data mining and new data processing for petroleum and coal companies. In particular, this method provides a new solution to production problems such as the determination of super-thin reservoirs and super-close faults, and the detection of goaf and abandoned tunnels.