On June 7, 2025, the Institute of High Energy Physics at the Chinese Academy of Sciences triumphantly announced that the first compact, high-power metamaterial klystron designed for the P-band in the China Spallation Neutron Source (CSNS) linear accelerator has successfully passed rigorous tests and acceptance inspections at the Dongguan Research Department. This landmark achievement signifies a profound breakthrough in the key technologies essential for the China Spallation Neutron Source. Serving as the linchpin of the linear accelerator's radiofrequency power source system, the klystron is pivotal in providing the necessary energy and impetus to the beam current. Prior to this development, all such advanced equipment was reliant on imports, underscoring the significance of this independent research and development effort as a testament to China's formidable prowess in the realm of high-end radiofrequency device innovation.