Integrating results from geochronology, numerical simulation and petrology , author proposed that the Cenozoic volcanism in the North China(NC) and Northea st China(NEC) was caused by lithosphere delamination and related force convectio n in asthenosphere. During Palaeogene, lithosphere delamination occurred in the central parts of NC and NEC, and induced Palaeogene volcanism. Then the mantle c onvection cell grew with time. The thermo-mechanic erosion of the convection res ulted in delamination under marginal regions of NC and NEC, and caused Neogene-Q uaternary volcanism in these regions. Our proposal was supported by terrestrial heat flow data, Bouguer anomaly inversion and neotectonic studies.