<p>Unconventional oil and gas such as shale oil are widely distributed. However, the complex geology and strong vertical heterogeneity of reservoir bring great challenges to the design of hydraulic fracturing. By combining acoustic emission (AE) monitoring technology, a physical simulation experimental method for real-time inversion of hydraulic fracturing fractures was developed, and the influence mechanisms of different stress differences, fracturing fluid viscosities, and injection rates on the cross-layer propagation of hydraulic fractures and the activation of bedding planes (BPs) were explored. The tensile and shear signals during the experiment were classified, and the AE signals at different layers were analyzed. From both macroscopic and microscopic perspectives, the spatial morphology and influence mechanisms of fracture propagation were revealed. Research shows that more tensile signals are generated when fractures propagate across layers, while more shear signals are produced when BPs are activated. During the vertical cross-layer propagation of hydraulic fractures, mainly tensile fractures are formed; when BPs are activated, mainly shear fractures occur. Furthermore, under high horizontal stress difference and high viscosity fracturing fluid conditions, hydraulic fractures are more inclined to directly penetrate the BPs, resulting in relatively simple fracture geometries. Increasing the injection rate facilitates hydraulic fractures to penetrate through the restrictions of BPs, forming main fractures while simultaneously activating BP fractures to create fracture branches. The findings of this research are expected to provide references for optimizing field process parameters and formulating fracturing plans for shale reservoirs.</p>