Abstract: The continuous improvement of automotive lightweighting and crash safety performance imposes dual demands on steels: higher strength and better toughness. In 2025, the 2 200 MPa grade Al-Si coated hot stamping steel(named “Xiaomi Steel”), jointly developed by academician team led by Wang Guodong from Northeastern University, Easyforming Technology Co., Ltd., and Xiaomi EV, achieved its world-first mass production and vehicle installation, breaking through the long-standing “strong but brittle” bottleneck of martensitic steels with strengths above 2 000 MPa. This paper systematically describes the core technological breakthroughs and engineering values of this steel from four aspects: innovative material design, thin coating interface control, hydrogen-induced delayed cracking assessment, and industrial application. Based on the thin Al-Si coating technology, we further demonstrate that through a low-alloy design concept of “Mo and Ni-free”plus Al addition, combined with banded structure sensitivity factor optimization, Cottrell atmosphere kinetics control, and dispersed nano-vanadium carbide precipitation control, a 2 200 MPa grade hot stamping steel has been successfully and stably produced, exhibiting an as-quenched tensile strength near 2 200 MPa, a post-paint-baking tensile strength of 2 000 MPa, and a transverse three-point bending angle of 45°. Its fracture strain is comparable to 2 000 MPa grade steels made by foreign companies, while the strength is increased by about 10% and the alloy cost per ton is significantly reduced. Meanwhile, the development of the thin Al-Si coating technology and the brand-new rapid assessment method for hydrogen-induced delayed cracking provides key technical support for the large-scale application of the 2 200 MPa grade material and its risk control. At present, this material comes standard across Xiaomi YU7 and the new generation SU7 models, and has won the First Prize for Scientific and Technological Innovation Achievement from the China Association for the Promotion of Industry-University-Research Collaboration. This achievement marks a leap from “following” to “leading” in the field of high-performance automotive steels in China, and also provides a typical case of industry-university-research collaborative innovation.