<p>Ultrafine metal nanoparticles are crucial for various applications, such as energy storage, catalysis, electronics, and biomedicine, owing to their high surface-to-volume ratio and unique electronic properties. However, conventional nanoparticle synthesis methods often face challenges like irregular shapes and agglomeration, leading to compromised functionality. To address these challenges, this paper introduces a novel, rapid, high-temperature thermal radiation heating for the ultrafast synthesis and dispersion of metal nanoparticles. Utilizing the heating properties of carbon materials, the direct Joule heating generated by them rises to 1800–2000&#xa0;K within ~ 200&#xa0;ms, followed by cooling to room temperature at a rate of 2 × 10³&#xa0;K&#xa0;s⁻¹. The large thermal gradient achieved during this process mitigated the kinetic limitations of metal meltisng and recrystallization, thereby preventing abnormal grain growth and facilitating the production of ultrafine metal nanoparticles. Additionally, the nucleation and growth advantages confined environment, which ensured the uniform dispersion of the metal nanoparticles. Carbon thermal shock can be extended to the rapid production of various metal nanoparticles, including silicon, aluminum, silver, nickel, copper, tin, and germanium. Compared with conventional methods, known for being slower and less efficient, carbon thermal shock enables faster synthesis (on the millisecond scale) and improved dispersion. This study provides a universal strategy for achieving uniform distribution of nanoparticles across various fields.</p> Graphical abstract <p></p>