Abstract: To clarify the research priorities for three-dimensional fracture-network stimulation in ultra-deep shale gas reservoirs in China, this study systematically reviews the geological and engineering characteristics, hydraulic fracturing practices, and post-fracturing flowback and gas-testing responses of shale gas blocks with true vertical depths greater than 4,500 m worldwide. Development practices in Woodford, Mancos, and representative blocks of the Sichuan Basin are analyzed, and the adaptability of fracturing technologies and differences in post-fracturing production behavior under varying reservoir conditions are summarized. In the Woodford Shale, favorable conditions such as well-developed natural fractures, low stress contrast, and relatively high brittleness have enabled the development of a three-dimensional fracture-network stimulation mode characterized by small cluster spacing, medium-to-high fluid intensity, high proppant loading, fine-grained proppants, and temporary plugging and diversion. In contrast, ultra-deep shale gas reservoirs in China are generally characterized by high temperature, high in-situ stress, high stress contrast, high closure pressure, and multiple interlayers. These conditions lead to high treating pressures, narrow proppant-placement windows, and limited fracture-network complexity. Some wells also exhibit high flowback recovery and high post-fracturing liquid production. The analysis indicates that natural fractures or micro faults are key geological factors controlling complex fracture development and high gas deliverability, while high net pressure and effective far-field fracture propping are essential engineering guarantees for high and stable production. Existing geological and engineering sweet-spot evaluation criteria, fracturing technologies, and monitoring methods cannot fully meet the efficient stimulation requirements of different types of ultra-deep shale gas reservoirs in China. It is therefore recommended to establish dual sweet-spot evaluation criteria suitable for ultra-deep shale gas reservoirs, to develop differentiated three-dimensional fracture-network stimulation technologies, shut-in and flowback management strategies, and far-field fracture monitoring techniques for different reservoir types, and ultimately to build an integrated evaluation-fracturing-production technical system adapted to ultra-deep shale gas development in different regions of China.