Abstract: It is difficult to predict the "sweet spot" owing to the complex lithofacies, rapid longitudinal change, and strong heterogeneity of shale reservoirs.It is important to clarify the physical characteristics of shale strata with complex lithofacies to improve the accuracy of logging interpretations and quantitative seismic predictions.In this study, 33 samples were collected from the second oil group of the lower segment of the Xingouzui Formation in the Chentuokou Sag, and basic physical property measurements and cross-band rock physics experiments composed of low-frequency (1~1 000 Hz) strain-stress tests and ultrasonic band (1 MHz) tests were conducted to obtain the rock physical parameters of the shales.Combined with geological understanding, we studied the correlation mechanism between the elastic anisotropy and physical properties of the reservoir in terms of lithology, diagenetic minerals, and microscopic pore structure to provide cross-band elastic attributes for the seismic identification of favorable lithofacies in shale reservoirs.The results showed that the shale strata of oil group II, the lower member of the Xingouzui Formation had extremely low porosity and permeability.Dolomite intergranular pores were less developed, whereas the laminated structure, terrigenous clastic minerals, and their contents positively affected dolomitic shale porosity.Moreover, the relationship between the physical data of the mineral and microstructure and the elastic property data measured by ultrasonic testing showed that the mineral composition and pore structure were the main factors influencing the elastic properties of shale.The acoustic anisotropy of the shale in the area was controlled by the laminated structure, horizontal fractures, and oriented alignment of clay minerals.Finally, the velocity dispersion of all samples was estimated based on the cross-band experimental data and dispersion theoretical model to provide cross-band (2.2 Hz, 24.0 Hz, 1.0×10⁴ Hz, and 1.0×10⁶ Hz) elastic parameter combinations of λρ, ν, Z_p, and v_P/v_S to identify favorable lithofacies.The results of this study can provide guidance and support for the joint application of cross-frequency (seismic, well-logging, and laboratory ultrasonic) data based on rock physics experiments and theoretical modelling, as well as quantitative seismic prediction studies.