Abstract: From 28 July to 2 August, 2023, North China experienced a rare and persistent extreme rainfall event. In this study, we analyze moisture sources and the development of mesoscale convective systems (MCSs) across three stages, defined by the spatial progression of rainfall and the prevailing mesoscale environment. In Stage one, rainfall centers were located over northern Henan, southwestern–central Hebei, and the mountainous fringes south of Beijing. Moisture mainly originated from the western North Pacific and the South China Sea, while a weakening post-landfall vortex of Typhoon Doksuri directed multiple MCSs into the region. The vortex began affecting northern Henan at 1800 UTC on July 28 and dissipated over southwestern Shanxi at 1200 UTC 30 July. In Stage two, convection intensified, producing peak local rainfall, and rainfall centers shifted to central–northern Hebei, southern Beijing, and northern Tianjin. Typhoon Khanun moved northward into the central East China Sea, supplying moisture from the western North Pacific. A warm-type shear line with easterly winds favored east–west oriented MCS development. In Stage three, total rainfall decreased, with centers over northeastern Beijing and northwestern Tianjin. A southerly low-level jet dominated, transporting moisture from the northwestern Pacific and the offshore region south of Fujian. MCSs evolved rapidly in scale and intensity, leading to localized heavy rainfall.