Abstract: In the Zhongtaishan-Bajiaochang area of the central Sichuan Basin, the second member of the Jurassic Shaximiao Formation develops multiple stages of channel sand bodies that are frequently superimposed vertically. P-wave and S-wave velocity slices provide distinct advantages for studying their distribution characteristics and vertical evolution patterns. Based on high-resolution sequence stratigraphy and sedimentary responses to changes in accommodation space, the second member of the Jurassic Shaximiao Formation was divided into 4 fourth-order sequences. By integrating core, logging facies, and seismic facies data, the study determined that channel facies dominate. Each sand group was formed by the superimposition and migration of multiple channel sand bodies. Seismic reflections were mainly characterized by continuous to weakly continuous parallel reflections, with some bright spots observable in contrast, representing channel deposits. To address the challenge of severe overlap of wave impedance of sandstone and mudstone, P-wave and S-wave velocities were identified as sensitive parameters for effective lithology discrimination. Based on pre-stack simultaneous inversion, a P-wave to S-wave velocity ratio data volume capable of distinguishing sandstone from mudstone was obtained. Using this lithologically meaningful data volume, seismic sedimentology research was then carried out. Typical stratigraphic slices were employed to identify river channels and classify river types by drawing analogies between modern and ancient systems, and the controlling effect of accommodation space on channel scale was discussed. The results showed that the second member of the Jurassic Shaximiao Formation in the Zhongtaishan-Bajiaochang area was dominated by meandering river facies, with 18 stages of river channels developed vertically. Two main river types were developed, i.e., straight rivers and low-sinuosity meandering rivers, and in some slices, multiple river types coexisted. Sand bodies No. 7-9 were developed under conditions of low accommodation space, where channels overlapped and were large in scale, making them key targets for further exploration and development of the second member of the Jurassic Shaximiao Formation.